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Materials Science › Electronic, Optical and Magnetic Materials

Gold and Silver Nanoparticles Synthesis and Applications

Works Count: 59780

Description

This cluster of papers focuses on the synthesis, properties, and applications of plasmonic nanoparticles, particularly gold nanoparticles. It covers a wide range of topics including surface-enhanced Raman spectroscopy, nanomedicine, biosensing, photothermal therapy, nanofabrication, and the development of nanoscale optical devices for various biomedical applications.

Keywords

Plasmonic Nanoparticles; Gold Nanoparticles; Surface-Enhanced Raman Spectroscopy; Nanomedicine; Biosensing; Photothermal Therapy; Nanofabrication; Nanoscale Optical Devices; Biomedical Applications; Molecular Sensing

Biosensing with plasmonic nanosensors

2008-05-23
Jeffrey N. Anker , W. Paige Hall , Olga Lyandres +3 more

Recent Advances in the Liquid-Phase Syntheses of Inorganic Nanoparticles

2004-08-20
Brian L. Cushing , Vladimir Kolesnichenko , Charles J. O’Connor
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRecent Advances in the Liquid-Phase Syntheses of Inorganic NanoparticlesBrian L. Cushing, Vladimir L. Kolesnichenko, and Charles J. O'ConnorView Author Information Advanced Materials Research Institute, University of New … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRecent Advances in the Liquid-Phase Syntheses of Inorganic NanoparticlesBrian L. Cushing, Vladimir L. Kolesnichenko, and Charles J. O'ConnorView Author Information Advanced Materials Research Institute, University of New Orleans, New Orleans, Louisiana 70148-2820 Cite this: Chem. Rev. 2004, 104, 9, 3893–3946Publication Date (Web):August 20, 2004Publication History Received28 October 2003Published online20 August 2004Published inissue 1 September 2004https://pubs.acs.org/doi/10.1021/cr030027bhttps://doi.org/10.1021/cr030027bresearch-articleACS PublicationsCopyright © 2004 American Chemical SocietyRequest reuse permissionsArticle Views35286Altmetric-Citations2536LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Gold,Metal nanoparticles,Metals,Nanoparticles,Oxides Get e-Alerts

Some Interesting Properties of Metals Confined in Time and Nanometer Space of Different Shapes

2001-01-18
Mostafa A. El‐Sayed
The properties of a material depend on the type of motion its electrons can execute, which depends on the space available for them (i.e., on the degree of their spatial … The properties of a material depend on the type of motion its electrons can execute, which depends on the space available for them (i.e., on the degree of their spatial confinement). Thus, the properties of each material are characterized by a specific length scale, usually on the nanometer dimension. If the physical size of the material is reduced below this length scale, its properties change and become sensitive to its size and shape. In this Account we describe some of the observed new chemical, optical, and thermal properties of metallic nanocrystals when their size is confined to the nanometer length scale and their dynamical processes are observed on the femto- to picosecond time scale.

Shape-Controlled Synthesis of Gold and Silver Nanoparticles

2002-12-12
Yugang Sun , Younan Xia
Monodisperse samples of silver nanocubes were synthesized in large quantities by reducing silver nitrate with ethylene glycol in the presence of poly(vinyl pyrrolidone) (PVP). These cubes were single crystals and … Monodisperse samples of silver nanocubes were synthesized in large quantities by reducing silver nitrate with ethylene glycol in the presence of poly(vinyl pyrrolidone) (PVP). These cubes were single crystals and were characterized by a slightly truncated shape bounded by [100], [110], and [111] facets. The presence of PVP and its molar ratio (in terms of repeating unit) relative to silver nitrate both played important roles in determining the geometric shape and size of the product. The silver cubes could serve as sacrificial templates to generate single-crystalline nanoboxes of gold: hollow polyhedra bounded by six [100] and eight [111] facets. Controlling the size, shape, and structure of metal nanoparticles is technologically important because of the strong correlation between these parameters and optical, electrical, and catalytic properties.

Rapid synthesis of Au, Ag, and bimetallic Au core–Ag shell nanoparticles using Neem (Azadirachta indica) leaf broth

2004-04-13
S. Shiv Shankar , Akhilesh Rai , Absar Ahmad +1 more

Noble Metals on the Nanoscale: Optical and Photothermal Properties and Some Applications in Imaging, Sensing, Biology, and Medicine

2008-05-01
Prashant K. Jain , Xiaohua Huang , Ivan H. El‐Sayed +1 more
Noble metal nanostructures attract much interest because of their unique properties, including large optical field enhancements resulting in the strong scattering and absorption of light. The enhancement in the optical … Noble metal nanostructures attract much interest because of their unique properties, including large optical field enhancements resulting in the strong scattering and absorption of light. The enhancement in the optical and photothermal properties of noble metal nanoparticles arises from resonant oscillation of their free electrons in the presence of light, also known as localized surface plasmon resonance (LSPR). The plasmon resonance can either radiate light (Mie scattering), a process that finds great utility in optical and imaging fields, or be rapidly converted to heat (absorption); the latter mechanism of dissipation has opened up applications in several new areas. The ability to integrate metal nanoparticles into biological systems has had greatest impact in biology and biomedicine. In this Account, we discuss the plasmonic properties of gold and silver nanostructures and present examples of how they are being utilized for biodiagnostics, biophysical studies, and medical therapy. For instance, taking advantage of the strong LSPR scattering of gold nanoparticles conjugated with specific targeting molecules allows the molecule-specific imaging and diagnosis of diseases such as cancer. We emphasize in particular how the unique tunability of the plasmon resonance properties of metal nanoparticles through variation of their size, shape, composition, and medium allows chemists to design nanostructures geared for specific bio-applications. We discuss some interesting nanostructure geometries, including nanorods, nanoshells, and nanoparticle pairs, that exhibit dramatically enhanced and tunable plasmon resonances, making them highly suitable for bio-applications. Tuning the nanostructure shape (e.g., nanoprisms, nanorods, or nanoshells) is another means of enhancing the sensitivity of the LSPR to the nanoparticle environment and, thereby, designing effective biosensing agents. Metal nanoparticle pairs or assemblies display distance-dependent plasmon resonances as a result of field coupling. A universal scaling model, relating the plasmon resonance frequency to the interparticle distance in terms of the particle size, becomes potentially useful for measuring nanoscale distances (and their changes) in biological systems. The strong plasmon absorption and photothermal conversion of gold nanoparticles has been exploited in cancer therapy through the selective localized photothermal heating of cancer cells. For nanorods or nanoshells, the LSPR can be tuned to the near-infrared region, making it possible to perform in vivo imaging and therapy. The examples of the applications of noble metal nanostructures provided herein can be readily generalized to other areas of biology and medicine because plasmonic nanomaterials exhibit great range, versatility, and systematic tunability of their optical attributes.

Determining the Size and Shape Dependence of Gold Nanoparticle Uptake into Mammalian Cells

2006-03-01
Devika B. Chithrani , Arezou A. Ghazani , Warren C. W. Chan
We investigated the intracellular uptake of different sized and shaped colloidal gold nanoparticles. We showed that kinetics and saturation concentrations are highly dependent upon the physical dimensions of the nanoparticles … We investigated the intracellular uptake of different sized and shaped colloidal gold nanoparticles. We showed that kinetics and saturation concentrations are highly dependent upon the physical dimensions of the nanoparticles (e.g., uptake half-life of 14, 50, and 74 nm nanoparticles is 2.10, 1.90, and 2.24 h, respectively). The findings from this study will have implications in the chemical design of nanostructures for biomedical applications (e.g., tuning intracellular delivery rates and amounts by nanoscale dimensions and engineering complex, multifunctional nanostructures for imaging and therapeutics).
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Single Molecule Detection Using Surface-Enhanced Raman Scattering (SERS)

1997-03-03
Katrin Kneipp , Yang Wang , Harald Kneipp +4 more
By exploiting the extremely large effective cross sections ( ${10}^{\ensuremath{-}17}--{10}^{\ensuremath{-}16}{\mathrm{cm}}^{2}/\mathrm{molecule}$) available from surface-enhanced Raman scattering (SERS), we achieved the first observation of single molecule Raman scattering. Measured spectra of a … By exploiting the extremely large effective cross sections ( ${10}^{\ensuremath{-}17}--{10}^{\ensuremath{-}16}{\mathrm{cm}}^{2}/\mathrm{molecule}$) available from surface-enhanced Raman scattering (SERS), we achieved the first observation of single molecule Raman scattering. Measured spectra of a single crystal violet molecule in aqueous colloidal silver solution using one second collection time and about $2\ifmmode\times\else\texttimes\fi{}{10}^{5}\mathrm{W}/{\mathrm{cm}}^{2}$ nonresonant near-infrared excitation show a clear ``fingerprint'' of its Raman features between 700 and $1700{\mathrm{cm}}^{\ensuremath{-}1}$. Spectra observed in a time sequence for an average of 0.6 dye molecule in the probed volume exhibited the expected Poisson distribution for actually measuring 0, 1, 2, or 3 molecules.

The golden age: gold nanoparticles for biomedicine

2011-11-23
Erik C. Dreaden , Alaaldin M. Alkilany , Xiaohua Huang +2 more
Gold nanoparticles have been used in biomedical applications since their first colloidal syntheses more than three centuries ago. However, over the past two decades, their beautiful colors and unique electronic … Gold nanoparticles have been used in biomedical applications since their first colloidal syntheses more than three centuries ago. However, over the past two decades, their beautiful colors and unique electronic properties have also attracted tremendous attention due to their historical applications in art and ancient medicine and current applications in enhanced optoelectronics and photovoltaics. In spite of their modest alchemical beginnings, gold nanoparticles exhibit physical properties that are truly different from both small molecules and bulk materials, as well as from other nanoscale particles. Their unique combination of properties is just beginning to be fully realized in range of medical diagnostic and therapeutic applications. This critical review will provide insights into the design, synthesis, functionalization, and applications of these artificial molecules in biomedicine and discuss their tailored interactions with biological systems to achieve improved patient health. Further, we provide a survey of the rapidly expanding body of literature on this topic and argue that gold nanotechnology-enabled biomedicine is not simply an act of 'gilding the (nanomedicinal) lily', but that a new 'Golden Age' of biomedical nanotechnology is truly upon us. Moving forward, the most challenging nanoscience ahead of us will be to find new chemical and physical methods of functionalizing gold nanoparticles with compounds that can promote efficient binding, clearance, and biocompatibility and to assess their safety to other biological systems and their long-term term effects on human health and reproduction (472 references).
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Elucidating the Mechanism of Cellular Uptake and Removal of Protein-Coated Gold Nanoparticles of Different Sizes and Shapes

2007-04-28
Devika B. Chithrani , Warren C. W. Chan
We investigated the mechanism by which transferrin-coated gold nanoparticles (Au NP) of different sizes and shapes entered mammalian cells. We determined that transferrin-coated Au NP entered the cells via clathrin-mediated … We investigated the mechanism by which transferrin-coated gold nanoparticles (Au NP) of different sizes and shapes entered mammalian cells. We determined that transferrin-coated Au NP entered the cells via clathrin-mediated endocytosis pathway. The NPs exocytosed out of the cells in a linear relationship to size. This was different than the relationship between uptake and size. Furthermore, we developed a mathematical equation to predict the relationship of size versus exocytosis for different cell lines. These studies will provide guidelines for developing NPs for imaging and drug delivery applications, which will require "controlling" NP accumulation rate. These studies will also have implications in determining nanotoxicity.

Photoinduced Conversion of Silver Nanospheres to Nanoprisms

2001-11-30
Rongchao Jin , Y. Charles Cao , Chad A. Mirkin +3 more
A photoinduced method for converting large quantities of silver nanospheres into triangular nanoprisms is reported. The photo-process has been characterized by time-dependent ultraviolet-visible spectroscopy and transmission electron microscopy, allowing for … A photoinduced method for converting large quantities of silver nanospheres into triangular nanoprisms is reported. The photo-process has been characterized by time-dependent ultraviolet-visible spectroscopy and transmission electron microscopy, allowing for the observation of several key intermediates in and characteristics of the conversion process. This light-driven process results in a colloid with distinctive optical properties that directly relate to the nanoprism shape of the particles. Theoretical calculations coupled with experimental observations allow for the assignment of the nanoprism plasmon bands and for the first identification of two distinct quadrupole plasmon resonances for a nanoparticle. Unlike the spherical particles they are derived from that Rayleigh light-scatter in the blue, these nanoprisms exhibit scattering in the red, which could be useful in developing multicolor diagnostic labels on the basis not only of nanoparticle composition and size but also of shape.

A Hybridization Model for the Plasmon Response of Complex Nanostructures

2003-10-16
Emil Prodan , Corey Radloff , Naomi J. Halas +1 more
We present a simple and intuitive picture, an electromagnetic analog of molecular orbital theory, that describes the plasmon response of complex nanostructures of arbitrary shape. Our model can be understood … We present a simple and intuitive picture, an electromagnetic analog of molecular orbital theory, that describes the plasmon response of complex nanostructures of arbitrary shape. Our model can be understood as the interaction or "hybridization" of elementary plasmons supported by nanostructures of elementary geometries. As an example, the approach is applied to the important case of a four-layer concentric nanoshell, where the hybridization of the plasmons of the inner and outer nanoshells determines the resonant frequencies of the multilayer nanostructure.

Gold nanoparticles in nanomedicine: preparations, imaging, diagnostics, therapies and toxicity

2009-01-01
Élodie Boisselier , Didier Astruc
This critical review provides an overall survey of the basic concepts and up-to-date literature results concerning the very promising use of gold nanoparticles (AuNPs) for medicinal applications. It includes AuNP … This critical review provides an overall survey of the basic concepts and up-to-date literature results concerning the very promising use of gold nanoparticles (AuNPs) for medicinal applications. It includes AuNP synthesis, assembly and conjugation with biological and biocompatible ligands, plasmon-based labeling and imaging, optical and electrochemical sensing, diagnostics, therapy (drug vectorization and DNA/gene delivery) for various diseases, in particular cancer (also Alzheimer, HIV, hepatitis, tuberculosis, arthritis, diabetes) and the essential in vitro and in vivo toxicity. It will interest the medicine, chemistry, spectroscopy, biochemistry, biophysics and nanoscience communities (211 references).

Enhancement and Quenching of Single-Molecule Fluorescence

2006-03-21
Pascal Anger , Palash Bharadwaj , LukĂĄĹĄ NovotnĂ˝
We present an experimental and theoretical study of the fluorescence rate of a single molecule as a function of its distance to a laser-irradiated gold nanoparticle. The local field enhancement … We present an experimental and theoretical study of the fluorescence rate of a single molecule as a function of its distance to a laser-irradiated gold nanoparticle. The local field enhancement leads to an increased excitation rate whereas nonradiative energy transfer to the particle leads to a decrease of the quantum yield (quenching). Because of these competing effects, previous experiments showed either fluorescence enhancement or fluorescence quenching. By varying the distance between molecule and particle we show the first experimental measurement demonstrating the continuous transition from fluorescence enhancement to fluorescence quenching. This transition cannot be explained by treating the particle as a polarizable sphere in the dipole approximation.

Preparation and Growth Mechanism of Gold Nanorods (NRs) Using Seed-Mediated Growth Method

2003-04-17
Babak Nikoobakht , Mostafa A. El‐Sayed
A method is used for preparing gold NRs with aspect ratios ranging from 1.5 to 10 for which the surface plasmon absorption maxima are between 600 and 1300 nm. This … A method is used for preparing gold NRs with aspect ratios ranging from 1.5 to 10 for which the surface plasmon absorption maxima are between 600 and 1300 nm. This method has been adapted from a previously published seed-mediated growth method (Jana et al. Adv. Mater. 2001, 13, 1389). The disadvantages and limitations of the earlier method (i.e., formation of noncylindrical NRs, φ-shaped particles, and formation of a large fraction of spherical particles) have been overcome by use of a hexadecyltrimethylammonium bromide (CTAB)-capped seed instead of a citrate-capped one. In a single-component surfactant system, the silver content of the growth solution was used to grow NRs to a desired length. This results in reproducible formation of NRs with aspect ratios ranging from 1.5 to 4.5. To grow longer NRs with aspect ratios ranging from 4.6 to 10, a binary surfactant mixture composed of benzyldimethylhexadecylammoniumchloride (BDAC) and CTAB was used. NRs are grown in this mixture either by aging or by addition of a growth solution suitable to shorter NRs. Effects of the silver ion and the cosurfactant along with the growth mechanism of NRs are discussed.

Anisotropic Metal Nanoparticles: Synthesis, Assembly, and Optical Applications

2005-06-18
Catherine J. Murphy , Tapan K. Sau , Anand Gole +5 more
This feature article highlights work from the authors' laboratories on the synthesis, assembly, reactivity, and optical applications of metallic nanoparticles of nonspherical shape, especially nanorods. The synthesis is a seed-mediated … This feature article highlights work from the authors' laboratories on the synthesis, assembly, reactivity, and optical applications of metallic nanoparticles of nonspherical shape, especially nanorods. The synthesis is a seed-mediated growth procedure, in which metal salts are reduced initially with a strong reducing agent, in water, to produce ∼4 nm seed particles. Subsequent reduction of more metal salt with a weak reducing agent, in the presence of structure-directing additives, leads to the controlled formation of nanorods of specified aspect ratio and can also yield other shapes of nanoparticles (stars, tetrapods, blocks, cubes, etc.). Variations in reaction conditions and crystallographic analysis of gold nanorods have led to insight into the growth mechanism of these materials. Assembly of nanorods can be driven by simple evaporation from solution or by rational design with molecular-scale connectors. Short nanorods appear to be more chemically reactive than long nanorods. Finally, optical applications in sensing and imaging, which take advantage of the visible light absorption and scattering properties of the nanorods, are discussed.

Nanosphere Lithography: A Versatile Nanofabrication Tool for Studies of Size-Dependent Nanoparticle Optics

2001-05-09
Christy L. Haynes , Richard P. Van Duyne
Nanosphere lithography (NSL) is an inexpensive, simple to implement, inherently parallel, high throughput, materials general nanofabrication technique capable of producing an unexpectedly large variety of nanoparticle structures and well-ordered 2D … Nanosphere lithography (NSL) is an inexpensive, simple to implement, inherently parallel, high throughput, materials general nanofabrication technique capable of producing an unexpectedly large variety of nanoparticle structures and well-ordered 2D nanoparticle arrays. This article describes our recent efforts to broaden the scope of NSL to include strategies for the fabrication of several new nanoparticle structural motifs and their characterization by atomic force microscopy. NSL has also been demonstrated to be well-suited to the synthesis of size-tunable noble metal nanoparticles in the 20−1000 nm range. This characteristic of NSL has been especially valuable for investigating the fascinating richness of behavior manifested in size-dependent nanoparticle optics. The use of localized surface plasmon resonance (LSPR) spectroscopy to probe the size-tunable optical properties of Ag nanoparticles and their sensitivity to the local, external dielectric environment (viz., the nanoenvironment) is discussed in detail. More specifically, the effects of nanoparticle size, shape, interparticle spacing, nanoparticle-substrate interaction, solvent, dielectric overlayers, and molecular adsorbates on the LSPR spectrum of Ag nanoparticles are presented. This systematic study of the fundamentals of nanoparticle optics promises to find application in the field of chemical and biological nanosensors; herein, the initial data demonstrate that LSPR spectroscopy of Ag nanoparticles can be used to sense specifically bound analytes with zeptomole per nanoparticle detection limits and no detectable nonspecific binding.

Determination of Size and Concentration of Gold Nanoparticles from UV−Vis Spectra

2007-04-26
Wolfgang Haiss , Nguyễn Thị Kim Thanh , Jenny Aveyard +1 more
The dependence of the optical properties of spherical gold nanoparticles on particle size and wavelength were analyzed theoretically using multipole scattering theory, where the complex refractive index of gold was … The dependence of the optical properties of spherical gold nanoparticles on particle size and wavelength were analyzed theoretically using multipole scattering theory, where the complex refractive index of gold was corrected for the effect of a reduced mean free path of the conduction electrons in small particles. To compare these theoretical results to experimental data, gold nanoparticles in the size range of 5 to 100 nm were synthesized and characterized with TEM and UV−vis. Excellent agreement was found between theory and experiment. It is shown that the data produced here can be used to determine both size and concentration of gold nanoparticles directly from UV−vis spectra. Equations for this purpose are derived, and the precision of various methods is discussed. The major aim of this work is to provide a simple and fast method to determine size and concentration of nanoparticles.

Controlled Nucleation for the Regulation of the Particle Size in Monodisperse Gold Suspensions

1973-01-01
G. Frens

Plasmons in Strongly Coupled Metallic Nanostructures

2011-05-04
Naomi J. Halas , Surbhi Lal , Wei‐Shun Chang +2 more
ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTPlasmons in Strongly Coupled Metallic NanostructuresNaomi J. Halas†‡§, Surbhi Lal†, Wei-Shun Chang‡, Stephan Link†‡, and Peter Nordlander*†§View Author Information† § †Department of Electrical and Computer Engineering, ‡Department … ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTPlasmons in Strongly Coupled Metallic NanostructuresNaomi J. Halas†‡§, Surbhi Lal†, Wei-Shun Chang‡, Stephan Link†‡, and Peter Nordlander*†§View Author Information† § †Department of Electrical and Computer Engineering, ‡Department of Chemistry, and §Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States*E-mail: [email protected]Cite this: Chem. Rev. 2011, 111, 6, 3913–3961Publication Date (Web):May 4, 2011Publication History Received18 February 2011Published online4 May 2011Published inissue 8 June 2011https://pubs.acs.org/doi/10.1021/cr200061khttps://doi.org/10.1021/cr200061kreview-articleACS PublicationsCopyright © 2011 American Chemical SocietyRequest reuse permissionsArticle Views55067Altmetric-Citations2614LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Metal nanoparticles,Nanoparticles,Plasmonic nanoparticles,Plasmonics,Plasmons Get e-Alerts

Wet Chemical Synthesis of High Aspect Ratio Cylindrical Gold Nanorods

2001-04-21
Nikhil R. Jana , Latha Gearheart , Catherine J. Murphy
Gold nanorods with aspect ratios of 4.6 ± 1.2, 13 ± 2, and 18 ± 2.5 (all with 16 ± 3 nm short axis) are prepared by a seeding growth … Gold nanorods with aspect ratios of 4.6 ± 1.2, 13 ± 2, and 18 ± 2.5 (all with 16 ± 3 nm short axis) are prepared by a seeding growth approach in the presence of an aqueous miceller template. Citrate-capped 3.5 nm diameter gold particles, prepared by the reduction of HAuCl4 with borohydride, are used as the seed. The aspect ratio of the nanorods is controlled by varying the ratio of seed to metal salt. The long rods are isolated from spherical particles by centrifugation.

Effect of Surface Properties on Nanoparticle–Cell Interactions

2009-10-20
Ayush Verma , Francesco Stellacci
The interaction of nanomaterials with cells and lipid bilayers is critical in many applications such as phototherapy, imaging, and drug/gene delivery. These applications require a firm control over nanoparticle-cell interactions, … The interaction of nanomaterials with cells and lipid bilayers is critical in many applications such as phototherapy, imaging, and drug/gene delivery. These applications require a firm control over nanoparticle-cell interactions, which are mainly dictated by surface properties of nanoparticles. This critical Review presents an understanding of how synthetic and natural chemical moieties on the nanoparticle surface (in addition to nanoparticle shape and size) impact their interaction with lipid bilayers and cells. Challenges for undertaking a systematic study to elucidate nanoparticle-cell interactions are also discussed.

SERS: Materials, applications, and the future

2012-01-01
Bhavya Sharma , Renee R. Frontiera , Anne-Isabelle Henry +2 more
Surface enhanced Raman spectroscopy (SERS) is a powerful vibrational spectroscopy technique that allows for highly sensitive structural detection of low concentration analytes through the amplification of electromagnetic fields generated by … Surface enhanced Raman spectroscopy (SERS) is a powerful vibrational spectroscopy technique that allows for highly sensitive structural detection of low concentration analytes through the amplification of electromagnetic fields generated by the excitation of localized surface plasmons. SERS has progressed from studies of model systems on roughened electrodes to highly sophisticated studies, such as single molecule spectroscopy. We summarize the current state of knowledge concerning the mechanism of SERS and new substrate materials. We highlight recent applications of SERS including sensing, spectroelectrochemistry, single molecule SERS, and real-world applications. We also discuss contributions to the field from the Van Duyne group. This review concludes with a discussion of future directions for this field including biological probing with UV-SERS, tip-enhanced Raman spectroscopy, and ultrafast SERS.

Shape-Controlled Synthesis of Colloidal Platinum Nanoparticles

1996-06-28
Temer S. Ahmadi , Zhong Lin Wang , Travis C. Green +2 more
The shapes and sizes of platinum nanoparticles were controlled by changes in the ratio of the concentration of the capping polymer material to the concentration of the platinum cations used … The shapes and sizes of platinum nanoparticles were controlled by changes in the ratio of the concentration of the capping polymer material to the concentration of the platinum cations used in the reductive synthesis of colloidal particles in solution at room temperature. Tetrahedral, cubic, irregular-prismatic, icosahedral, and cubo-octahedral particle shapes were observed, whose distribution was dependent on the concentration ratio of the capping polymer material to the platinum cation. Controlling the shape of platinum nanoparticles is potentially important in the field of catalysis.

Spectral Properties and Relaxation Dynamics of Surface Plasmon Electronic Oscillations in Gold and Silver Nanodots and Nanorods

1999-09-10
Stephan Link , Mostafa A. El‐Sayed
The field of nanoparticle research has drawn much attention in the past decade as a result of the search for new materials. Size confinement results in new electronic and optical … The field of nanoparticle research has drawn much attention in the past decade as a result of the search for new materials. Size confinement results in new electronic and optical properties, possibly suitable for many electronic and optoelectronic applications. A characteristic feature of noble metal nanoparticles is the strong color of their colloidal solutions, which is caused by the surface plasmon absorption. This article describes our studies of the properties of the surface plasmon absorption in metal nanoparticles that range in size between 10 and 100 nm. The effects of size, shape, and composition on the plasmon absorption maximum and its bandwidth are discussed. Furthermore, the optical response of the surface plasmon absorption due to excitation with femtosecond laser pulses allowed us to follow the electron dynamics (electron−electron and electron−phonon scattering) in these metal nanoparticles. It is found that the electron−phonon relaxation processes in nanoparticles, which are smaller than the electron mean free path, are independent of their size or shape. Intense laser heating of the electrons in these particles is also found to cause a shape transformation (photoisomerization of the rods into spheres or fragmentation), which depends on the laser pulse energy and pulse width.

Gold Nanoparticles: Assembly, Supramolecular Chemistry, Quantum-Size-Related Properties, and Applications toward Biology, Catalysis, and Nanotechnology

2003-12-20
Marie‐Christine Daniel , Didier Astruc

Shell-isolated nanoparticle-enhanced Raman spectroscopy

2010-03-16
Jianfeng Li , Yi Huang , Yong Ding +7 more

Cancer Cell Imaging and Photothermal Therapy in the Near-Infrared Region by Using Gold Nanorods

2006-01-21
Xiaohua Huang , Ivan H. El‐Sayed , Wei Qian +1 more
Due to strong electric fields at the surface, the absorption and scattering of electromagnetic radiation by noble metal nanoparticles are strongly enhanced. These unique properties provide the potential of designing … Due to strong electric fields at the surface, the absorption and scattering of electromagnetic radiation by noble metal nanoparticles are strongly enhanced. These unique properties provide the potential of designing novel optically active reagents for simultaneous molecular imaging and photothermal cancer therapy. It is desirable to use agents that are active in the near-infrared (NIR) region of the radiation spectrum to minimize the light extinction by intrinsic chromophores in native tissue. Gold nanorods with suitable aspect ratios (length divided by width) can absorb and scatter strongly in the NIR region (650−900 nm). In the present work, we provide an in vitro demonstration of gold nanorods as novel contrast agents for both molecular imaging and photothermal cancer therapy. Nanorods are synthesized and conjugated to anti-epidermal growth factor receptor (anti-EGFR) monoclonal antibodies and incubated in cell cultures with a nonmalignant epithelial cell line (HaCat) and two malignant oral epithelial cell lines (HOC 313 clone 8 and HSC 3). The anti-EGFR antibody-conjugated nanorods bind specifically to the surface of the malignant-type cells with a much higher affinity due to the overexpressed EGFR on the cytoplasmic membrane of the malignant cells. As a result of the strongly scattered red light from gold nanorods in dark field, observed using a laboratory microscope, the malignant cells are clearly visualized and diagnosed from the nonmalignant cells. It is found that, after exposure to continuous red laser at 800 nm, malignant cells require about half the laser energy to be photothermally destroyed than the nonmalignant cells. Thus, both efficient cancer cell diagnostics and selective photothermal therapy are realized at the same time.

Surface-enhanced Raman scattering

1998-01-01
Alan Campion , Patanjali Kambhampati
We present an introduction to surface-enhanced Raman scattering (SERS) which reviews the basic experimental facts and the essential features of the mechanisms which have been proposed to account for the … We present an introduction to surface-enhanced Raman scattering (SERS) which reviews the basic experimental facts and the essential features of the mechanisms which have been proposed to account for the observations. We then review very recent fundamental developments which include: SERS from single particles and single molecules; SERS from fractal clusters and surfaces; and new insights into the chemical enhancement mechanism of SERS.

Calculated Absorption and Scattering Properties of Gold Nanoparticles of Different Size, Shape, and Composition: Applications in Biological Imaging and Biomedicine

2006-03-18
Prashant K. Jain , Kyeong-Seok Lee , Ivan H. El‐Sayed +1 more
The selection of nanoparticles for achieving efficient contrast for biological and cell imaging applications, as well as for photothermal therapeutic applications, is based on the optical properties of the nanoparticles. … The selection of nanoparticles for achieving efficient contrast for biological and cell imaging applications, as well as for photothermal therapeutic applications, is based on the optical properties of the nanoparticles. We use Mie theory and discrete dipole approximation method to calculate absorption and scattering efficiencies and optical resonance wavelengths for three commonly used classes of nanoparticles: gold nanospheres, silica−gold nanoshells, and gold nanorods. The calculated spectra clearly reflect the well-known dependence of nanoparticle optical properties viz. the resonance wavelength, the extinction cross-section, and the ratio of scattering to absorption, on the nanoparticle dimensions. A systematic quantitative study of the various trends is presented. By increasing the size of gold nanospheres from 20 to 80 nm, the magnitude of extinction as well as the relative contribution of scattering to the extinction rapidly increases. Gold nanospheres in the size range commonly employed (∼40 nm) show an absorption cross-section 5 orders higher than conventional absorbing dyes, while the magnitude of light scattering by 80-nm gold nanospheres is 5 orders higher than the light emission from strongly fluorescing dyes. The variation in the plasmon wavelength maximum of nanospheres, i.e., from ∼520 to 550 nm, is however too limited to be useful for in vivo applications. Gold nanoshells are found to have optical cross-sections comparable to and even higher than the nanospheres. Additionally, their optical resonances lie favorably in the near-infrared region. The resonance wavelength can be rapidly increased by either increasing the total nanoshell size or increasing the ratio of the core-to-shell radius. The total extinction of nanoshells shows a linear dependence on their total size, however, it is independent of the core/shell radius ratio. The relative scattering contribution to the extinction can be rapidly increased by increasing the nanoshell size or decreasing the ratio of the core/shell radius. Gold nanorods show optical cross-sections comparable to nanospheres and nanoshells, however, at much smaller effective size. Their optical resonance can be linearly tuned across the near-infrared region by changing either the effective size or the aspect ratio of the nanorods. The total extinction as well as the relative scattering contribution increases rapidly with the effective size, however, they are independent of the aspect ratio. To compare the effectiveness of nanoparticles of different sizes for real biomedical applications, size-normalized optical cross-sections or per micron coefficients are calculated. Gold nanorods show per micron absorption and scattering coefficients that are an order of magnitude higher than those for nanoshells and nanospheres. While nanorods with a higher aspect ratio along with a smaller effective radius are the best photoabsorbing nanoparticles, the highest scattering contrast for imaging applications is obtained from nanorods of high aspect ratio with a larger effective radius.
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Surface-enhanced spectroscopy

1985-07-01
Martin Moskovits
In 1978 it was discovered, largely through the work of Fleischmann, Van Duyne, Creighton, and their coworkers that molecules adsorbed on specially prepared silver surfaces produce a Raman spectrum that … In 1978 it was discovered, largely through the work of Fleischmann, Van Duyne, Creighton, and their coworkers that molecules adsorbed on specially prepared silver surfaces produce a Raman spectrum that is at times a millionfold more intense than expected. This effect was dubbed surface-enhanced Raman scattering (SERS). Since then the effect has been demonstrated with many molecules and with a number of metals, including Cu, Ag, Au, Li, Na, K, In, Pt, and Rh. In addition, related phenomena such as surface-enhanced second-harmonic generation, four-wave mixing, absorption, and fluorescence have been observed. Although not all fine points of the enhancement mechanism have been clarified, the majority view is that the largest contributor to the intensity amplification results from the electric field enhancement that occurs in the vicinity of small, interacting metal particles that are illuminated with light resonant or near resonant with the localized surface-plasmon frequency of the metal structure. Small in this context is gauged in relation to the wavelength of light. The special preparations required to produce the effect, which include among other techniques electrochemical oxidation-reduction cycling, deposition of metal on very cold substrates, and the generation of metal-island films and colloids, is now understood to be necessary as a means of producing surfaces with appropriate electromagnetic resonances that may couple to electromagnetic fields either by generating rough films (as in the case of the former two examples) or by placing small metal particles in close proximity to one another (as in the case of the latter two). For molecules chemisorbed on SERS-active surface there exists a "chemical enhancement" in addition to the electromagnetic effect. Although difficult to measure accurately, the magnitude of this effect rarely exceeds a factor of 10 and is best thought to arise from the modification of the Raman polarizability tensor of the adsorbate resulting from the formation of a complex between the adsorbate and the metal. Rather than an enhancement mechanism, the chemical effect is more logically to be regarded as a change in the nature and identity of the adsorbate.

Exploitation of Localized Surface Plasmon Resonance

2004-10-04
Eliza Hutter , JĂĄnos H. Fendler
Abstract Recent advances in the exploitation of localized surface plasmons (charge density oscillations confined to metallic nanoparticles and nanostructures) in nanoscale optics and photonics, as well as in the construction … Abstract Recent advances in the exploitation of localized surface plasmons (charge density oscillations confined to metallic nanoparticles and nanostructures) in nanoscale optics and photonics, as well as in the construction of sensors and biosensors, are reviewed here. In particular, subsequent to brief surveys of the most‐commonly used methods of preparation and arraying of materials with localized surface plasmon resonance (LSPR), and of the optical manifestations of LSPR, attention will be focused on the exploitation of metallic nanostructures as waveguides; as optical transmission, information storage, and nanophotonic devices; as switches; as resonant light scatterers (employed in the different near‐field scanning optical microscopies); and finally as sensors and biosensors.

Controlling the Synthesis and Assembly of Silver Nanostructures for Plasmonic Applications

2011-03-11
Matthew Rycenga , Claire M. Cobley , Jie Zeng +5 more
ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTControlling the Synthesis and Assembly of Silver Nanostructures for Plasmonic ApplicationsMatthew Rycenga, Claire M. Cobley, Jie Zeng, Weiyang Li, Christine H. Moran, Qiang Zhang, Dong Qin, and … ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTControlling the Synthesis and Assembly of Silver Nanostructures for Plasmonic ApplicationsMatthew Rycenga, Claire M. Cobley, Jie Zeng, Weiyang Li, Christine H. Moran, Qiang Zhang, Dong Qin, and Younan Xia*View Author Information Department of Biomedical Engineering, Washington University, St. Louis, Missouri 63130, United States*E-mail: [email protected]Cite this: Chem. Rev. 2011, 111, 6, 3669–3712Publication Date (Web):March 11, 2011Publication History Received20 August 2010Published online11 March 2011Published inissue 8 June 2011https://pubs.acs.org/doi/10.1021/cr100275dhttps://doi.org/10.1021/cr100275dreview-articleACS PublicationsCopyright © 2011 American Chemical SocietyRequest reuse permissionsArticle Views55225Altmetric-Citations2370LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Metals,Nanoparticles,Nanostructures,Plasmonics,Surface plasmon resonance Get e-Alerts
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Surface Enhanced Raman Scattering Enhancement Factors: A Comprehensive Study

2007-08-23
Eric C. Le Ru , E. Blackie , Matthias Meyer +1 more
This paper presents an in-depth study of Surface Enhanced Raman Scattering (SERS) enhancement factors (EFs) and cross-sections, including several issues often overlooked. In particular, various possible rigorous definitions of the … This paper presents an in-depth study of Surface Enhanced Raman Scattering (SERS) enhancement factors (EFs) and cross-sections, including several issues often overlooked. In particular, various possible rigorous definitions of the SERS EFs are introduced and discussed in the context of SERS applications, such as analytical chemistry and single molecule SERS. These definitions highlight the importance of a careful characterization of the non-SERS cross-sections of the probes under consideration. This aspect is illustrated by experimental results for the non-SERS cross-sections of representative SERS probes along with average SERS EFs for the same probes. In addition, the accurate experimental determination of single molecule enhancement factors is tackled with two recently developed techniques, namely: bi-analyte SERS (BiASERS) and temperature-dependent SERS vibrational pumping. We demonstrate that SERS EFs as low as 107, as opposed to the figure of 1014 often claimed in the literature, are sufficient for the observation of single molecule SERS signals, with maximum single molecule EFs typically on the order of ∼1010.

Adsorption and surface-enhanced Raman of dyes on silver and gold sols

1982-08-01
P. C. Lee , Dan Meisel
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAdsorption and surface-enhanced Raman of dyes on silver and gold solsP. C. Lee and D. MeiselCite this: J. Phys. Chem. 1982, 86, 17, 3391–3395Publication Date (Print):August 1, … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAdsorption and surface-enhanced Raman of dyes on silver and gold solsP. C. Lee and D. MeiselCite this: J. Phys. Chem. 1982, 86, 17, 3391–3395Publication Date (Print):August 1, 1982Publication History Published online1 May 2002Published inissue 1 August 1982https://pubs.acs.org/doi/10.1021/j100214a025https://doi.org/10.1021/j100214a025research-articleACS PublicationsRequest reuse permissionsArticle Views25315Altmetric-Citations4092LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access options Get e-Alerts

Shape Control of Colloidal Metal Nanocrystals

2008-02-26
Andrea R. Tao , Susan E. Habas , Peidong Yang
Abstract Colloidal metal nanoparticles are emerging as key materials for catalysis, plasmonics, sensing, and spectroscopy. Within these applications, control of nanoparticle shape lends increasing functionality and selectivity. Shape‐controlled nanocrystals possess … Abstract Colloidal metal nanoparticles are emerging as key materials for catalysis, plasmonics, sensing, and spectroscopy. Within these applications, control of nanoparticle shape lends increasing functionality and selectivity. Shape‐controlled nanocrystals possess well‐defined surfaces and morphologies because their nucleation and growth are controlled at the atomic level. An overall picture of shaped metal particles is presented, with a particular focus on solution‐based syntheses for the noble metals. General strategies for synthetic control are discussed, emphasizing key factors that result in anisotropic, nonspherical growth such as crystallographically selective adsorbates and seeding processes.

The Optical Properties of Metal Nanoparticles: The Influence of Size, Shape, and Dielectric Environment

2002-12-21
K. Lance Kelly , Eduardo A. Coronado , Lin Lin Zhao +1 more
The optical properties of metal nanoparticles have long been of interest in physical chemistry, starting with Faraday's investigations of colloidal gold in the middle 1800s. More recently, new lithographic techniques … The optical properties of metal nanoparticles have long been of interest in physical chemistry, starting with Faraday's investigations of colloidal gold in the middle 1800s. More recently, new lithographic techniques as well as improvements to classical wet chemistry methods have made it possible to synthesize noble metal nanoparticles with a wide range of sizes, shapes, and dielectric environments. In this feature article, we describe recent progress in the theory of nanoparticle optical properties, particularly methods for solving Maxwell's equations for light scattering from particles of arbitrary shape in a complex environment. Included is a description of the qualitative features of dipole and quadrupole plasmon resonances for spherical particles; a discussion of analytical and numerical methods for calculating extinction and scattering cross-sections, local fields, and other optical properties for nonspherical particles; and a survey of applications to problems of recent interest involving triangular silver particles and related shapes.

Probing Single Molecules and Single Nanoparticles by Surface-Enhanced Raman Scattering

1997-02-21
Shuming Nie , Steven R. Emory
Optical detection and spectroscopy of single molecules and single nanoparticles have been achieved at room temperature with the use of surface-enhanced Raman scattering. Individual silver colloidal nanoparticles were screened from … Optical detection and spectroscopy of single molecules and single nanoparticles have been achieved at room temperature with the use of surface-enhanced Raman scattering. Individual silver colloidal nanoparticles were screened from a large heterogeneous population for special size-dependent properties and were then used to amplify the spectroscopic signatures of adsorbed molecules. For single rhodamine 6G molecules adsorbed on the selected nanoparticles, the intrinsic Raman enhancement factors were on the order of 10 14 to 10 15 , much larger than the ensemble-averaged values derived from conventional measurements. This enormous enhancement leads to vibrational Raman signals that are more intense and more stable than single-molecule fluorescence.

Localized Surface Plasmon Resonance Spectroscopy and Sensing

2006-10-26
Katherine A. Willets , Richard P. Van Duyne
Localized surface plasmon resonance (LSPR) spectroscopy of metallic nanoparticles is a powerful technique for chemical and biological sensing experiments. Moreover, the LSPR is responsible for the electromagnetic-field enhancement that leads … Localized surface plasmon resonance (LSPR) spectroscopy of metallic nanoparticles is a powerful technique for chemical and biological sensing experiments. Moreover, the LSPR is responsible for the electromagnetic-field enhancement that leads to surface-enhanced Raman scattering (SERS) and other surface-enhanced spectroscopic processes. This review describes recent fundamental spectroscopic studies that reveal key relationships governing the LSPR spectral location and its sensitivity to the local environment, including nanoparticle shape and size. We also describe studies on the distance dependence of the enhanced electromagnetic field and the relationship between the plasmon resonance and the Raman excitation energy. Lastly, we introduce a new form of LSPR spectroscopy, involving the coupling between nanoparticle plasmon resonances and adsorbate molecular resonances. The results from these fundamental studies guide the design of new sensing experiments, illustrated through applications in which researchers use both LSPR wavelength-shift sensing and SERS to detect molecules of chemical and biological relevance.

Surface‐Enhanced Raman Spectroscopy: Concepts and Chemical Applications

2014-04-07
Sebastian SchlĂźcker
Abstract Surface‐enhanced Raman scattering (SERS) has become a mature vibrational spectroscopic technique during the last decades and the number of applications in the chemical, material, and in particular life sciences … Abstract Surface‐enhanced Raman scattering (SERS) has become a mature vibrational spectroscopic technique during the last decades and the number of applications in the chemical, material, and in particular life sciences is rapidly increasing. This Review explains the basic theory of SERS in a brief tutorial and—based on original results from recent research—summarizes fundamental aspects necessary for understanding SERS and provides examples for the preparation of plasmonic nanostructures for SERS. Chemical applications of SERS are the centerpiece of this Review. They cover a broad range of topics such as catalysis and spectroelectrochemistry, single‐molecule detection, and (bio)analytical chemistry.

Size and Temperature Dependence of the Plasmon Absorption of Colloidal Gold Nanoparticles

1999-05-01
Stephan Link , Mostafa A. El‐Sayed
The size and temperature dependence of the plasmon absorption is studied for 9, 15, 22, 48, and 99 nm gold nanoparticles in aqueous solution. The plasmon bandwidth is found to … The size and temperature dependence of the plasmon absorption is studied for 9, 15, 22, 48, and 99 nm gold nanoparticles in aqueous solution. The plasmon bandwidth is found to follow the predicted behavior as it increases with decreasing size in the intrinsic size region (mean diameter smaller than 25 nm), and also increases with increasing size in the extrinsic size region (mean diameter larger than 25 nm). Because of this pronounced size effect a homogeneous size distribution and therefore a homogeneous broadening of the plasmon band is concluded for all the prepared gold nanoparticle samples. By applying a simple two-level model the dephasing time of the coherent plasmon oscillation is calculated and found to be less than 5 fs. Furthermore, the temperature dependence of the plasmon absorption is examined. A small temperature effect is observed. This is consistent with the fact that the dominant electronic dephasing mechanism involves electron−electron interactions rather than electron−phonon coupling.

Interparticle Coupling Effect on the Surface Plasmon Resonance of Gold Nanoparticles: From Theory to Applications

2007-11-01
Sujit Kumar Ghosh , Tarasankar Pal
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInterparticle Coupling Effect on the Surface Plasmon Resonance of Gold Nanoparticles: From Theory to ApplicationsSujit Kumar Ghosh and Tarasankar PalView Author Information Department of Chemistry, Raidighi College, … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInterparticle Coupling Effect on the Surface Plasmon Resonance of Gold Nanoparticles: From Theory to ApplicationsSujit Kumar Ghosh and Tarasankar PalView Author Information Department of Chemistry, Raidighi College, Raidighi-743383, South 24-Parganas, India, and Department of Chemistry, Indian Institute of Technology, Kharagpur-721302, India Cite this: Chem. Rev. 2007, 107, 11, 4797–4862Publication Date (Web):November 14, 2007Publication History Received3 November 2006Published online14 November 2007Published inissue 1 November 2007https://pubs.acs.org/doi/10.1021/cr0680282https://doi.org/10.1021/cr0680282research-articleACS PublicationsCopyright © 2007 American Chemical SocietyRequest reuse permissionsArticle Views41633Altmetric-Citations2303LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Aggregation,Gold,Metal nanoparticles,Nanoparticles,Plasmonic nanoparticles Get e-Alerts

Shape‐Controlled Synthesis of Metal Nanocrystals: Simple Chemistry Meets Complex Physics?

2008-12-03
Younan Xia , Yujie Xiong , Byungkwon Lim +1 more
Abstract Nanocrystals are fundamental to modern science and technology. Mastery over the shape of a nanocrystal enables control of its properties and enhancement of its usefulness for a given application. … Abstract Nanocrystals are fundamental to modern science and technology. Mastery over the shape of a nanocrystal enables control of its properties and enhancement of its usefulness for a given application. Our aim is to present a comprehensive review of current research activities that center on the shape‐controlled synthesis of metal nanocrystals. We begin with a brief introduction to nucleation and growth within the context of metal nanocrystal synthesis, followed by a discussion of the possible shapes that a metal nanocrystal might take under different conditions. We then focus on a variety of experimental parameters that have been explored to manipulate the nucleation and growth of metal nanocrystals in solution‐phase syntheses in an effort to generate specific shapes. We then elaborate on these approaches by selecting examples in which there is already reasonable understanding for the observed shape control or at least the protocols have proven to be reproducible and controllable. Finally, we highlight a number of applications that have been enabled and/or enhanced by the shape‐controlled synthesis of metal nanocrystals. We conclude this article with personal perspectives on the directions toward which future research in this field might take.
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Why gold nanoparticles are more precious than pretty gold: Noble metal surface plasmon resonance and its enhancement of the radiative and nonradiative properties of nanocrystals of different shapes

2005-12-16
Susie Eustis , Mostafa A. El‐Sayed
This tutorial review presents an introduction to the field of noble metal nanoparticles and their current applications. The origin of the surface plasmon resonance and synthesis procedures are described. A … This tutorial review presents an introduction to the field of noble metal nanoparticles and their current applications. The origin of the surface plasmon resonance and synthesis procedures are described. A number of applications are presented that take advantage of the electromagnetic field enhancement of the radiative properties of noble metal nanoparticles resulting from the surface plasmon oscillations.

Nanoengineering of optical resonances

1998-05-01
Steven J. Oldenburg , Richard D. Averitt , Sarah L. Westcott +1 more

Spectroscopy of Single Hemoglobin Molecules by Surface Enhanced Raman Scattering

1999-11-22
Hongxing Xu , Erik J. Bjerneld , Mikael Käll +1 more
We demonstrate the detection of molecular vibrations in single hemoglobin (Hb) protein molecules attached to isolated and immobilized silver nanoparticles by surface enhanced Raman scattering (SERS). A comparison between calculation … We demonstrate the detection of molecular vibrations in single hemoglobin (Hb) protein molecules attached to isolated and immobilized silver nanoparticles by surface enhanced Raman scattering (SERS). A comparison between calculation and experiment indicates that electromagnetic field effects dominate the surface enhancement, and that single molecule Hb SERS is possible only for molecules situated between Ag particles. The vibrational spectra exhibit temporal fluctuations of unknown origin which appear to be characteristic of the single molecule detection limit.

Nanoparticle-mediated cellular response is size-dependent

2008-03-01
Wen Jiang , Betty Y.S. Kim , James T. Rutka +1 more

Localized Surface Plasmon Resonance Sensors

2011-06-08
Kathryn M. Mayer , Jason H. Hafner
ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTLocalized Surface Plasmon Resonance SensorsKathryn M. Mayer†§ and Jason H. Hafner*†‡§View Author Information† ‡ § †Department of Physics and Astronomy, ‡Department of Chemistry, and §Laboratory for Nanophotonics, … ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTLocalized Surface Plasmon Resonance SensorsKathryn M. Mayer†§ and Jason H. Hafner*†‡§View Author Information† ‡ § †Department of Physics and Astronomy, ‡Department of Chemistry, and §Laboratory for Nanophotonics, Rice University, Houston, Texas 77005, United States*E-mail: [email protected]Cite this: Chem. Rev. 2011, 111, 6, 3828–3857Publication Date (Web):June 8, 2011Publication History Received18 September 2010Published online8 June 2011Published inissue 8 June 2011https://pubs.acs.org/doi/10.1021/cr100313vhttps://doi.org/10.1021/cr100313vreview-articleACS PublicationsCopyright © 2011 American Chemical SocietyRequest reuse permissionsArticle Views63615Altmetric-Citations3313LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Gold,Metal nanoparticles,Nanoparticles,Sensors,Surface plasmon resonance Get e-Alerts

Present and Future of Surface-Enhanced Raman Scattering

2019-09-03
Judith Langer , Dorleta JimĂŠnez de Aberasturi , Javier Aizpurua +7 more
The discovery of the enhancement of Raman scattering by molecules adsorbed on nanostructured metal surfaces is a landmark in the history of spectroscopic and analytical techniques. Significant experimental and theoretical … The discovery of the enhancement of Raman scattering by molecules adsorbed on nanostructured metal surfaces is a landmark in the history of spectroscopic and analytical techniques. Significant experimental and theoretical effort has been directed toward understanding the surface-enhanced Raman scattering (SERS) effect and demonstrating its potential in various types of ultrasensitive sensing applications in a wide variety of fields. In the 45 years since its discovery, SERS has blossomed into a rich area of research and technology, but additional efforts are still needed before it can be routinely used analytically and in commercial products. In this Review, prominent authors from around the world joined together to summarize the state of the art in understanding and using SERS and to predict what can be expected in the near future in terms of research, applications, and technological development. This Review is dedicated to SERS pioneer and our coauthor, the late Prof. Richard Van Duyne, whom we lost during the preparation of this article.
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Surface-Enhanced Raman Spectroscopy

2008-05-07
Paul L. Stiles , Jon A. Dieringer , Nilam C. Shah +1 more
The ability to control the size, shape, and material of a surface has reinvigorated the field of surface-enhanced Raman spectroscopy (SERS). Because excitation of the localized surface plasmon resonance of … The ability to control the size, shape, and material of a surface has reinvigorated the field of surface-enhanced Raman spectroscopy (SERS). Because excitation of the localized surface plasmon resonance of a nanostructured surface or nanoparticle lies at the heart of SERS, the ability to reliably control the surface characteristics has taken SERS from an interesting surface phenomenon to a rapidly developing analytical tool. This article first explains many fundamental features of SERS and then describes the use of nanosphere lithography for the fabrication of highly reproducible and robust SERS substrates. In particular, we review metal film over nanosphere surfaces as excellent candidates for several experiments that were once impossible with more primitive SERS substrates (e.g., metal island films). The article also describes progress in applying SERS to the detection of chemical warfare agents and several biological molecules.

In Vivo distribution dynamics of Gold Nanoparticles: A quantitative analysis

2025-06-25
AngĂŠlica Bueno Barbezan , Wilmmer Alexander Arcos Rosero , Luis Almeida +3 more | Brazilian Journal of Radiation Sciences
This study evaluated the biodistribution of gum arabic-functionalized gold nanoparticles (GA-AuNPs) in Balb/C Nude mice following intravenous administration. Two activity regimens (200 µCi and 600 µCi) were analyzed at two … This study evaluated the biodistribution of gum arabic-functionalized gold nanoparticles (GA-AuNPs) in Balb/C Nude mice following intravenous administration. Two activity regimens (200 µCi and 600 µCi) were analyzed at two different time points (3 and 24 hours post-injection). The results showed predominant accumulation of GA-AuNPs in the liver, spleen, and gallbladder, suggesting hepatobiliary excretion as the primary clearance route. A reduction in liver uptake after 24 hours indicates potential nanoparticle metabolism or elimination. Although this study focused on intravenous delivery, previous work from our group using BSA-coated AuNPs administered intratumorally demonstrated higher tumor retention and reduced systemic accumulation, reinforcing the importance of administration route and surface coating in defining nanoparticle biodistribution. These findings contribute to the understanding of how delivery strategy influences nanoparticle bioavailability and support the development of safer and more targeted therapeutic platforms.

Retraction of “Lenalidomide (LENA) Hybrid Gold Complex Nanoparticles: Synthesis, Physicochemical Evaluation, and Perspectives in Nanomedicine”

2025-06-25
CĂŠlia Arib , Jolanda Spadavecchia | ACS Omega

Impact of shape on plasmon resonance in single silver nanoparticles: theoretical study

2025-06-25
Tetiana Bulavinets , Volodymyr Rokhiv , Vitalii Akopian +3 more | Molecular Crystals and Liquid Crystals

Sustainable Eco-Friendly Synthesis of Gold Nanoparticles Anchored on Graphene Oxide: Influence of Reductant Concentration on Nanoparticle Morphology

2025-06-25
Mariano Palomba , G. Carotenuto , Maria Grazia Raucci +2 more | Materials
Gold nanoparticles (AuNPs) anchored on graphene oxide (GO) have had a significant interest for their unique optical, electrical, and catalytic properties. This study presents an eco-friendly and sustainable synthesis of … Gold nanoparticles (AuNPs) anchored on graphene oxide (GO) have had a significant interest for their unique optical, electrical, and catalytic properties. This study presents an eco-friendly and sustainable synthesis of AuNPs on GO sheets using L-ascorbic acid (L-aa) as a green reducing agent and polyvinylpyrrolidone (PVP) as a stabilizer. The effect of reductant concentration on nanoparticle morphology was systematically investigated using UV–Visible spectroscopy and transmission electron microscopy (TEM). Results indicate the formation of AuNPs anchored on GO sheets and that an increase in the L-aa amount leads to both an increase in nanoparticle size and a morphological transition from spherical to irregular structures. The simultaneous nucleation and growth processes result in the formation of multiple families of nanostructures, as confirmed by TEM analysis, which reveals two distinct size distributions. At higher L-aa concentrations, the nanoparticles shape evolves into irregular morphologies due to selective growth along a preferential facet. This approach not only enables precise control over AuNP size and shape but also aligns with green chemistry principles, making it a promising route for applications in plasmonics, sensors, and photothermal therapy.

Application Areas of Nanotechnology

2025-06-25
| Royal Society of Chemistry eBooks
This chapter focuses on the diverse applications of nanotechnology, highlighting its impact across various industries such as healthcare, energy, electronics, and environmental sustainability. It discusses how nanoscale materials enhance sensors, … This chapter focuses on the diverse applications of nanotechnology, highlighting its impact across various industries such as healthcare, energy, electronics, and environmental sustainability. It discusses how nanoscale materials enhance sensors, coatings, catalysts, drug delivery systems, energy storage, structural materials, and water purification technologies. By improving efficiency, sensitivity, and durability, nanotechnology enables more precise, cost-effective, and environmentally friendly solutions. These innovations address critical challenges like pollution and energy efficiency, demonstrating nanotechnology’s potential to revolutionize industries and contribute to global sustainability efforts.

Resistivity-Controlled Switching Between Photoemission and Photothermoelectric Effects in Plasmonic Nanojunctions

2025-06-24
Jinxing Cao , Can Wang , Jiawang Guo +2 more | Optics Letters

Silver-Surface-Enhanced Raman Spectra of Berberine: Analyte-Induced Surface Changes, Variable Concentration Correlation, and Excitation Wavelength Dependence

2025-06-24
Ivan Kopal , Valerie SmelikovĂĄ | Langmuir
The utilization of surface-enhanced Raman scattering (SERS) for the analysis of biologically important compounds is strictly dependent on the properties of the substance being analyzed. One of them is berberine, … The utilization of surface-enhanced Raman scattering (SERS) for the analysis of biologically important compounds is strictly dependent on the properties of the substance being analyzed. One of them is berberine, a highly valued bioactive alkaloid sourced from various botanical species, which is renowned for its multifaceted health-enhancing attributes, although its potential negative effects have been widely discussed. Here, we aimed to investigate the properties of berberine influencing the SERS intensity. By modifying silver colloids by the wide range of berberine concentrations, we have revealed its ability to significantly affect the nanoparticle surface's properties, which results in complex concentration-dependent behavior. Characterization using extinction spectroscopy and transmission electron microscopy was performed to describe the ongoing effects. These results show that the tendency of silver nanoparticles to preferentially form assemblies with different geometries is the main reason for the nonlinear concentration dependence of the SERS signal. Additionally, we have investigated the effect of the excitation wavelength (532, 785, and 1064 nm) used. Such experiments not only provided the first comparison of the berberine SERS spectra measured with three different excitation wavelengths but also demonstrated that the observed intensity dependence is valid over a wide interval of excitation wavelengths. Apart from the physicochemical point of view, we also paid attention to effects important for possible analytical applications, such as reproducibility and long-term validity of the observed trends.

Geometric Representation of Tori-Based Nanoframes for Robust Resonance in NIR-II: A Numerical Study

2025-06-24
Fatema Alali | Plasmonics

Wavelength‐Dependent Differential Amplification of Raman Scattering by Chiral Gold Nanorods for Multiplexed Encoding

2025-06-24
Andrés Serrano‐Freijeiro , Carlos Renero‐Lecuna , Manuel Obelleiro‐Liz +7 more | Advanced Functional Materials
Abstract The application of wavelength‐dependent differential circularly polarized light‐induced surface‐enhanced Raman scattering (CPL‐SERS) is reported for codification and encryption, using colloidal chiral plasmonic nanoparticles. This study demonstrates that intrinsically chiral … Abstract The application of wavelength‐dependent differential circularly polarized light‐induced surface‐enhanced Raman scattering (CPL‐SERS) is reported for codification and encryption, using colloidal chiral plasmonic nanoparticles. This study demonstrates that intrinsically chiral Au nanorods (c‐AuNRs) encoded with achiral Raman reporters display unique optical activity. Right‐handed and left‐handed c‐AuNRs show positive or negative CPL‐SERS depending on the illumination wavelength (633 and 785 nm in this case), in correlation with their respective circular dichroism (CD) spectra. This effect enables c‐AuNR enantiomeric differentiation through evaluation of the CPL‐SERS response for each excitation wavelength. To showcase the potential of this approach, four encoded c‐AuNR dispersions were prepared, each with distinct handedness and Raman reporter combinations, and used to encode a four‐letter message on paper, which can be selectively decoded through CPL‐SERS, even when using only two Raman reporters. By switching between excitation wavelengths of 633 and 785 nm, inverted CPL‐SERS signals were recorded, therefore enhancing the versatility of the coding. The integration of chiral plasmonic nanoparticles and CPL‐SERS represents a highly tunable platform for advanced sensing, encryption, and codification, thereby expanding the functionality of plasmonic nanostructures in optical technologies.

The Influence of Cavity-Induced Plasmonic Coupling on Near-Field Enhancement in Cube-in-Cube Nanoparticles

2025-06-23
Sungbeen Park , Qiang Zhao , Soohyun Lee +3 more | Nano Letters
Internal nanostructures in plasmonic nanoparticles (NPs) have received comparatively limited attention, relative to external morphology and material composition. In particular, the influence of an internal cavity between the core and … Internal nanostructures in plasmonic nanoparticles (NPs) have received comparatively limited attention, relative to external morphology and material composition. In particular, the influence of an internal cavity between the core and shell on plasmonic coupling and field enhancement remains poorly understood. In this study, we investigate the effect of cavity size within cube-in-cube (CiC) NPs on interparticle plasmonic interactions. Using dimers as a model system, we find that increasing the internal cavity size significantly enhances near-field coupling despite maintaining a constant interparticle spacing. This enhancement correlates with stronger scattering signals, indicating that the cavity facilitates a more effective field propagation beyond the shell. These results demonstrate that the cavity not only is a passive structural feature but also actively modulates spatial field distribution and plasmon mode overlap. By tuning the internal cavity without altering the particle's outer geometry, both intra- and interparticle interactions can be precisely controlled, introducing internal architecture-based nanoscale optical control.

A Microfluidic Device to Realize Electrochemically Controlled SERS Detection in HPLC

2025-06-23
Maximilian E. Blaha , Julius Schwieger , Rico Warias +3 more | Analytical Chemistry
Surface-enhanced Raman spectroscopy (SERS) is a powerful technique for vibrational spectroscopy, but analyzing mixtures in solution remains challenging due to spectral overlap. Integrating SERS with a separation method, such as … Surface-enhanced Raman spectroscopy (SERS) is a powerful technique for vibrational spectroscopy, but analyzing mixtures in solution remains challenging due to spectral overlap. Integrating SERS with a separation method, such as high-performance liquid chromatography (HPLC), offers a promising solution. However, online coupling has been limited by the compatibility issues between the SERS process and flow-based systems, which can result in either irreversible analyte adsorption on the SERS substrate or insufficient interaction. This can lead to signal carry-over or low sensitivity. In this study, we present the first HPLC-compatible, pressure-stable SERS flow cell designed for real-time analysis under continuous flow. Fabricated entirely from glass using selective laser etching, the monolithic flow cell incorporates a silver-based SERS substrate and a counter electrode, enabling online electrochemical SERS (EC-SERS) experiments. Electrochemical control facilitates on-demand substrate activation, thereby enhancing signal intensity, extending substrate lifetime, and eliminating memory effects. This approach broadens the range of detectable analytes, including those that are traditionally difficult to detect using passive SERS. We demonstrate the performance of the system through HPLC-SERS analyses of model dyes (e.g., crystal violet, malachite green, and rhodamine) and pharmaceutical compounds (e.g., cyanocobalamin and folic acid). This innovation introduces a novel SERS-based HPLC detection method, supporting the seamless integration of SERS into high-throughput analytical workflows.

Molecule-Responsive SERS Sensors for Urine Diagnosis of Kidney Diseases Enhanced by Neural Networks

2025-06-22
Jiaqi Wang , Sijun Huang , Fanxiang Meng +7 more | Analytical Chemistry
Early diagnosis of kidney disease is crucial for treatment and prognosis. Compared with kidney biopsy, a noninvasive urine-based diagnosis method of kidney disease can be more convenient and less painful … Early diagnosis of kidney disease is crucial for treatment and prognosis. Compared with kidney biopsy, a noninvasive urine-based diagnosis method of kidney disease can be more convenient and less painful for patients. Urine is closely associated with kidney disease, including nephritis, kidney failure, and kidney cancer. Since it contains various biomolecules, including small-molecule metabolites, proteins, and so on, urine is an appropriate sample for diagnosing and monitoring kidney disease progression. Herein, we developed a liquid biopsy method for diagnosing various kidney diseases based on a specific SERS sensing mode combined with neural network models, which allows an integrated response to multiple types of targets with a single probe and facilitates the detection of complex samples from multiple target groups. Compared to label-free SERS, this method relies on changes in the probe molecule, which facilitates the sensitivity of the assay. Two kinds of silver nanoparticle-casting films assist this method with the surface decoration of molecule-responsive Raman reporter molecules: p-mercaptobenzoic acid (MBA) and p-aminothiophenol (PATP). MBA responds to amino components in urine by SERS spectral changes caused by molecular polarizability. PATP illustrates the level of small-molecule metabolites in urine according to SERS changes resulting from the rate of the hot hole-catalyzed reactions. These interactions were evidenced by density functional theory and molecular docking simulations. Through these two SERS sensors, we acquired the SERS data sets of urine samples and established a classifier by incorporating neural network models, enabling the effective discrimination of healthy and kidney disease samples. The method is helpful for clinical validation and shows promise for use in long-term kidney disease monitoring programs.

Amplification of Photochemical Chiroptical Activity of Chiral Gold Nanocubes

2025-06-22
Shashank K. Gahlaut , Óscar Ávalos‐Ovando , Ryeong Myeong Kim +6 more | Small
Abstract Chiral plasmonic nanostructures enable exceptionally high dissymmetry factors (g‐factors) compared to chiral molecules and present unparalleled opportunities in light manipulation, polarization‐sensitive photochemistry, and chiral sensing. Here polarization‐dependent plasmonic chemistry … Abstract Chiral plasmonic nanostructures enable exceptionally high dissymmetry factors (g‐factors) compared to chiral molecules and present unparalleled opportunities in light manipulation, polarization‐sensitive photochemistry, and chiral sensing. Here polarization‐dependent plasmonic chemistry on chiral gold nanocubes (AuNCs) is presented, leveraging the high sensitivity of surface‐enhanced Raman scattering (SERS). The AuNCs exhibit strong optical activity and localized surface plasmon resonances acting as highly efficient nanoscale light antennae. Employing the hot electron‐induced dehalogenation of 8‐Bromoadenine as a model reaction, it is demonstrated that circularly polarized light induces asymmetric reaction rates due to circular dichroism (CD) in hot electron generation efficiency. Astonishingly, the photochemical g‐factor, quantified by the differential reaction rate coefficients under left‐handed and right‐handed circularly polarized light, surpasses its optical counterpart and can be further enhanced by laser intensity. Remarkably, multilayer assemblies of AuNCs exhibit a reversal in photochemical CD, which is tuneable via laser power and enables further g‐factor enhancement. Comprehensive electromagnetic simulations of extinction spectra and hot electron generation maps corroborate the profound impact of particle arrangement on the optical g‐factor and the g‐factor for hot‐electron generation. This work demonstrates a systematic approach to enhance the photochemical chiroptical response of chiral AuNCs, paving the way for extraordinary control over chemical reactions with light.

Deciphering the Effect of Protein on Different Types of Target Signals in SERS Detection

2025-06-21
Shuna Mi , Yuhang Du , Shaofeng Yuan +4 more | Analytical Chemistry
The matrix effect remains a significant challenge for the practical application of surface-enhanced Raman spectroscopy (SERS), with proteins being one of the most common interfering components. In this study, melamine … The matrix effect remains a significant challenge for the practical application of surface-enhanced Raman spectroscopy (SERS), with proteins being one of the most common interfering components. In this study, melamine (strong SERS signals, weak protein binding), rhodamine 6G (R6G; strong SERS signals, strong protein binding), and phenobarbital (weak SERS signals, strong protein binding) were employed as representative target molecules of different types. α-lactalbumin (α-La), β-lactoglobulin (β-Lg), and bovine serum albumin (BSA) were selected as the model proteins. The effects of the protein concentration on SERS performance were systematically evaluated in terms of gold nanoparticle stability and adsorption behavior. At higher protein concentrations, the SERS signals of all three analytes were significantly attenuated with signal suppression intensifying as protein levels increased. This was attributed to the formation of a complete protein corona on the gold nanoparticle surface, which inhibited particle aggregation and reduced the adsorption capacity of analyte. In contrast, at lower protein concentrations, protein-induced aggregation negatively affected the SERS signals of melamine and R6G but enhanced the signal of phenobarbital, which lacks the intrinsic ability to induce gold nanoparticles aggregation. Additionally, the interaction between phenobarbital and proteins facilitated its adsorption onto the SERS substrate, further boosting its weak signal. These findings offer insights into the impact of proteins on SERS signals of different types of targets and provide a new idea for achieving SERS detection of targets such as phenobarbital, which exhibit inherently weak signals due to their inability to induce nanoparticle aggregation on their own, yet possess strong binding affinity with proteins.

Flexible Plasmonic Polymeric Membranes Consisting of Gold Nanoparticle Clusters as a Platform for Biomedical Sensing

2025-06-20
Federica Granata , Maria Laura Coluccio , Andrea Schirato +7 more | ACS Applied Nano Materials

Plasmonic and Dielectric Metasurfaces for Enhanced Spectroscopic Techniques

2025-06-20
Borja GarcĂ­a GarcĂ­a , MarĂ­a Gabriela FernĂĄndez-Manteca , Dimitrios C. Zografopoulos +5 more | Biosensors
Spectroscopic techniques such as Surface-Enhanced Raman Scattering (SERS), Surface-Enhanced Infrared Absorption (SEIRA), and Surface-Enhanced Fluorescence (SEF) are essential analytical techniques used to study the composition of materials by analyzing the … Spectroscopic techniques such as Surface-Enhanced Raman Scattering (SERS), Surface-Enhanced Infrared Absorption (SEIRA), and Surface-Enhanced Fluorescence (SEF) are essential analytical techniques used to study the composition of materials by analyzing the way materials scatter light, absorb infrared radiation or emit fluorescence signals. This provides information about their molecular structure and properties. However, traditional SERS, SEIRA, and SEF techniques can be limited in sensitivity, resolution, and reproducibility, hindering their ability to detect and analyze trace amounts of substances or complex molecular structures. Metasurfaces, a class of engineered two-dimensional metamaterials with unique optical properties, have emerged as a promising tool to overcome these limitations and enhance spectroscopic techniques. This article provides a state-of-the-art overview of metasurfaces for enhanced SERS, SEIRA and SEF, covering their theoretical background, different types, advantages, disadvantages, and potential applications.

Selective and Sensitive Dopamine Detection Using the Pictet–Spengler Reaction for Surface-Enhanced Raman Scattering

2025-06-20
Kunle Li , Xinyu Zheng , Jiancheng Feng +2 more | Analytical Chemistry
Dopamine (DA) presents significant challenges for direct quantification using surface-enhanced Raman scattering (SERS) due to its relatively small Raman cross section and the complexity of biological fluids. To address these … Dopamine (DA) presents significant challenges for direct quantification using surface-enhanced Raman scattering (SERS) due to its relatively small Raman cross section and the complexity of biological fluids. To address these limitations, this study introduces a novel approach combining the Pictet-Spengler (P-S) reaction with SERS for selective and sensitive DA detection. This method involves the preparation of aldehyde-modified layered double hydroxide, which effectively anchors DA molecules via the P-S reaction. This reaction is highly specific to DA, significantly enhancing the detection selectivity by overcoming interference from other molecules. Silver nanoparticles loaded with 4-mercaptophenylboronic acid are used as SERS probes for the indirect quantification of DA. The DA detection method demonstrated stability, achieving a linear response across a concentration range of 10-5-10-10 mol·L-1, with a minimum detection limit of 9.91 × 10-12 mol·L-1 (S/N = 3). The method also exhibited excellent performance in detecting DA in complex environments, such as simulated urine and cerebrospinal fluid samples, highlighting its potential application in diagnosing and monitoring neurological disorders.

Data Fusion Enhanced High-Dimensional SERS Fingerprints Construction via Dual-Wavelength and Multisubstrate Strategy for Precise Wastewater Identification

2025-06-20
Xueqing Wang , Lan Wei , Fan Li +2 more | Analytical Chemistry
It is well-known that traditional label-free surface-enhanced Raman spectroscopy (SERS) can capture fingerprint information on analyte, providing a foundation for target identification and differentiation. However, the conventional one-dimensional spectral data … It is well-known that traditional label-free surface-enhanced Raman spectroscopy (SERS) can capture fingerprint information on analyte, providing a foundation for target identification and differentiation. However, the conventional one-dimensional spectral data obtained through traditional SERS methods is insufficient for characterizing samples with complex chemical compositions, such as wastewater, or for tackling more intricate challenges, including tracing pollution sources, where a more comprehensive analytical profile is necessary. Herein, we introduce "SERSynergy", a data-fusion-driven machine learning approach that integrates dual-wavelength and multisubstrate data to generate a holistic SERS fingerprint, which allows for precise and robust wastewater identification. This method leverages complementary spectral features of wastewater samples by collecting a total of 12,000 spectra using four types of noble metal nanoparticles under two excitation wavelengths. A hybrid feature-decision fusion strategy cross-combined spectral features from various conditions to form high-dimensional fingerprints, which were then evaluated using optimized machine learning models and consolidated via probability-level fusion. The "SERSynergy" method demonstrated an identification accuracy of up to 99.67% for wastewater samples. Furthermore, when validated with blind sample testing, the method maintained an accuracy of 96.67%. Overall, the developed approach shows great promise for efficiently and accurately identifying wastewater samples, and it has potential applications in the precise acquisition of spectral features and identity discrimination in complex matrix samples.

Concentration Indicator Kit Based on Dandelion Propagation‐Inspired SERS Strategy

2025-06-19
Guoqian Li , Langlang Yi , Shiya Zhang +7 more | Advanced Materials
Abstract Surface‐enhanced Raman scattering (SERS) technology has been extensively employed for the detection of liquid samples in the biomedical field due to high sensitivity and non‐invasive characteristics. However, quantitative SERS … Abstract Surface‐enhanced Raman scattering (SERS) technology has been extensively employed for the detection of liquid samples in the biomedical field due to high sensitivity and non‐invasive characteristics. However, quantitative SERS detection is hindered by sophisticated instrumentation and complex calibration procedures, while qualitative analyses often provide insufficient concentration information for clinical diagnosis. Herein, a concentration indicator kit based on dandelion propagation‐inspired SERS strategy is developed for the semi‐quantitative detection of drug residues in urine. This strategy achieves significant signal enhancement through the synergistic effects of optimized hotspot construction and molecular adsorption, resulting in an analytical enhancement factor of 2.503 × 10⁵, which is 4143 times greater than that of silver nanoparticles. An innovative phenomenon termed the “concentration indicator” is discovered, wherein the SERS signal is dramatically enhanced at specific indicated concentrations while remaining weak at adjacent concentrations. The practical utility of this kit is validated through the detection of 2‐mercaptobenzothiazole in urine samples. The kit exhibits excellent performance in semi‐quantitative detection of standard solutions and simulated samples at high, indicated, and low concentrations. The concentration indicator opens new avenues for the development of simplified and reliable SERS‐based detection, offering a promising platform for bedside testing in medical diagnostics.

Uniform Spray‐Coated Flexible SERS Substrates for Enhanced Molecular Detection

2025-06-19
Shen Wang , Zhaoxin Wang , Xiaoxu Cao +7 more | Chemistry - An Asian Journal
Abstract Regulating uniformity and stability of substrates remains a key challenge in developments of flexible surface enhanced Raman spectroscopy (SERS) sensors. Herein, we fabricated a flexible SERS platform by integrating … Abstract Regulating uniformity and stability of substrates remains a key challenge in developments of flexible surface enhanced Raman spectroscopy (SERS) sensors. Herein, we fabricated a flexible SERS platform by integrating ultra‐stable nitrogen‐doped graphite‐coated gold nanoparticles (Au@NG) with a polydimethylsiloxane (PDMS) film via optimized microarray spray‐coating techniques, forming a composite substrate denoted as Au@NG@PDMS. The structure and chemical stability of the Au@NG nanoparticles were confirmed by TEM and Raman spectroscopy. The presence of a thin, nitrogen‐doped graphite shell effectively protected the Au core against acidic, alkaline, and oxidative environments. Benefiting from the superior mechanical flexibility of PDMS, the Au@NG@PDMS substrate maintained excellent SERS signal reproducibility under repeated bending and stretching cycles. Furthermore, we demonstrated that adjusting the solvent evaporation rate by selecting solvents in spraying process significantly improved the uniformity, reproducibility, and overall SERS performance of the substrate. Using this platform, we achieved highly sensitive and quantitative detection of crystal violet across a concentration range from 10 nM to 10 µM and successfully identified trace levels (20 ng/mL) of thiram residues directly on the surface of apples. The resulting flexible SERS substrate exhibits outstanding structural stability, signal uniformity, and surface conformability making it highly promising for practical applications in on‐site pesticide residue detection in agricultural monitoring.

Evolution of Morphological Parameters in Self-Assembled Ag Nanoparticle Arrays for High-Performance SERS

2025-06-19
Timofey Grishin , Л. С. Волкова , А. А. Дудин +4 more | Optical Materials

Numerical study of optical properties in core–shell nanoparticle for photothermal and thermoplasmonic heating effects

2025-06-19
Pooja Saini , Pradeep Bhatia | Journal of Electromagnetic Waves and Applications

Uptake of gold nanoparticles in HeLa cells observed by confocal microscopy shows dependency on particle size and shape

2025-06-19
Kimiya Pakravanan , Virginia Bazzurro , Marco Salerno +1 more | European Biophysics Journal

Gold-capped silver nanorods fabricated via glancing angle deposition: Label free, ultra stable SERS substrates for polymicrobial bacteria detection and antibiotics susceptibility testing

2025-06-19
Sneha Senapati , Arvind Kaushik , Manleen Kaur +4 more | Applied Surface Science

Polymer‐Driven Co‐Assembly of Achiral and Chiral Nanoparticles into Plasmonic Nanoclusters with Quantitatively Modulated Optical Chirality

2025-06-19
Chongyang Yao , Huibin He , Weijia Kong +5 more | Advanced Science
Abstract Chiral plasmonic nanoassemblies demonstrate enhanced chiral optical activity through plasmonic mode coupling, holding transformative potential for applications in sensing, catalysis, and quantum‐optical technologies. However, the mechanisms underlying this enhancement—particularly … Abstract Chiral plasmonic nanoassemblies demonstrate enhanced chiral optical activity through plasmonic mode coupling, holding transformative potential for applications in sensing, catalysis, and quantum‐optical technologies. However, the mechanisms underlying this enhancement—particularly the roles of structural geometry, plasmonic coupling, and chiral field amplification—remain incompletely elucidated. A significant challenge persists in designing coupled nanoassemblies with precisely controlled nanostructures to systematically investigate chirality enhancement. Departing from conventional approaches that incorporate chiral molecules, we present the co‐assembly of achiral and chiral plasmonic nanoparticles (NPs) into AB n ‐type nanoclustersand the correlation between inherent plasmonic chirality and the quantity of hotspots. Complementary polymer‐grafted achiral nanospheres and chiral nano arrows assemble into stable AB n clusters through a combination of electrostatic interactions and hydrogen bonding. The coordination number ( n ) of AB n can be tuned from 2 to 7 by adjusting polymer configurations through modulation of solution pH. The g ‐factor of AB n exhibits a linear increase with the n value of AB n . Simulation results indicate that the enhanced optical chirality arises from the increase in electric field strength due to the increasing number of hotspots within the NP assemblies.

SURFACE LATTICE RESONANCES FOR HIGH-PERFORMANCE SENSING: A STUDY ON GOLD NANOPARTICLE ARRAYS

2025-06-19
Ursula F. S. Roggero , Carlos Rojas-Bejarano , C. Fierro +4 more | Optics Express

Plasmonic Nanoparticle Monolayer‐Decorated Nanopipette Enabling in Situ Monitoring of Single‐Cell Redox Metabolism

2025-06-19
Lei Jiang , Mengqi Zhao , Hanbin Xu +7 more | Angewandte Chemie
The in‐depth study of how single cells respond to redox perturbations is pivotal for predicting cell fate decisions. Surface‐enhanced Raman spectroscopy (SERS)‐active nanopipettes hold promise for single‐cell analysis, yet challenges … The in‐depth study of how single cells respond to redox perturbations is pivotal for predicting cell fate decisions. Surface‐enhanced Raman spectroscopy (SERS)‐active nanopipettes hold promise for single‐cell analysis, yet challenges remain in achieving both signal sensitivity and reproducibility. Here, a plasmonic nanoparticle monolayer‐decorated nanopipette has been developed, which serves as a biomimetic endoscope to monitor single‐cell redox metabolism. This is accomplished by the conformal transferring of gold nanoparticle monolayer onto the nanopipette followed by the functionalization of redox‐responsive probes. The strong near‐field coupling within monolayer forms uniform hotspots, enabling highly sensitive and reproducible tracking of SERS signals changes triggered by redox species. Modulated by the nanopipette technology, the endoscope allows for in situ monitoring of global redox states with low invasiveness and high spatial resolution. Further study of ferroptosis events via simultaneous optical and electrical recording elucidates the correlation between redox imbalance and membrane damage during various ferroptosis‐inducers stimulation, which has not been observed at the single‐cell level. This work provides profound insights into the cellular redox dynamics, contributing to a deeper understanding of related physiopathological pathways.

Sensitive and Stable NCF/GO/Au@Ag SERS Substrate for Trace Detection of Polycyclic Aromatic Hydrocarbons

2025-06-19
Lili Kong , Xinna Yu , Qifang Sun +3 more | Polymers
Polycyclic aromatic hydrocarbons (PAHs) have attracted significant attention due to their severe threats to both ecological systems and human health. In this paper, a high-performance surface-enhanced Raman spectroscopy (SERS) substrate … Polycyclic aromatic hydrocarbons (PAHs) have attracted significant attention due to their severe threats to both ecological systems and human health. In this paper, a high-performance surface-enhanced Raman spectroscopy (SERS) substrate based on NCF/GO/Au@Ag nanocomposites was developed, which enabled sensitive and stable detection of PAHs. The NCF/GO/Au@Ag substrate synergistic utilizes the localized surface plasmon resonance (LSPR) effect of Au@Ag core-shell nanorods and the additional interfacial charge transfer provided by graphene oxide (GO) to exhibit extremely high sensitivity. And the three-dimensional fibrous network of nanocellulose (NCF) improved nanoparticle dispersion uniformity. Combined finite element simulations and experimental studies verified that the dual plasmonic resonances (512 nm and 772 nm) of Au@Ag nanorods optimally match 785 nm excitation, yielding an enhancement factor of 5.21 × 105. GO integration enhanced Raman signals by 1.68-fold through interfacial charge transfer, while the introduction of NCF reduced the signal relative standard deviation (RSD) from 36.88% to 4.29%. The NCF/GO/Au@Ag substrate achieved a detection limit of 10 μg/L for PAHs, demonstrating exceptional sensitivity and reproducibility.

Plasmonic Nanoparticle Monolayer‐Decorated Nanopipette Enabling in Situ Monitoring of Single‐Cell Redox Metabolism

2025-06-19
Lei Jiang , Mengqi Zhao , Hanbin Xu +7 more | Angewandte Chemie International Edition
The in‐depth study of how single cells respond to redox perturbations is pivotal for predicting cell fate decisions. Surface‐enhanced Raman spectroscopy (SERS)‐active nanopipettes hold promise for single‐cell analysis, yet challenges … The in‐depth study of how single cells respond to redox perturbations is pivotal for predicting cell fate decisions. Surface‐enhanced Raman spectroscopy (SERS)‐active nanopipettes hold promise for single‐cell analysis, yet challenges remain in achieving both signal sensitivity and reproducibility. Here, a plasmonic nanoparticle monolayer‐decorated nanopipette has been developed, which serves as a biomimetic endoscope to monitor single‐cell redox metabolism. This is accomplished by the conformal transferring of gold nanoparticle monolayer onto the nanopipette followed by the functionalization of redox‐responsive probes. The strong near‐field coupling within monolayer forms uniform hotspots, enabling highly sensitive and reproducible tracking of SERS signals changes triggered by redox species. Modulated by the nanopipette technology, the endoscope allows for in situ monitoring of global redox states with low invasiveness and high spatial resolution. Further study of ferroptosis events via simultaneous optical and electrical recording elucidates the correlation between redox imbalance and membrane damage during various ferroptosis‐inducers stimulation, which has not been observed at the single‐cell level. This work provides profound insights into the cellular redox dynamics, contributing to a deeper understanding of related physiopathological pathways.

Tuning the Catalytic and Optical Properties of Designable Metal Nanoframes

2025-06-18
Fahim El-Kassim M’madi Issimail , Hengzhi You , Sang Jun Sim +1 more | ACS Nano
Metal nanoframes (MNFs) have received significant attention in various fields, particularly in energy and biomedical fields. The rapid increase in energy consumption in modern societies and the need for improved … Metal nanoframes (MNFs) have received significant attention in various fields, particularly in energy and biomedical fields. The rapid increase in energy consumption in modern societies and the need for improved sensing devices have instigated researchers to explore various classes of materials. Nanoframes (NFs) particularly possess catalytic and optical properties, owing to their metallic composition and hollow structure compared to solid nanomaterials. Their physicochemical properties can be exploited to catalyze reactions for energy generation or tuned to enhance plasmonic properties such as localized surface plasmon resonance (LSPR) and surface-enhanced Raman spectroscopy (SERS) for sensing or imaging applications. Considerable improvements in design and synthetic protocols have been achieved to optimize material utility. In this review, we comprehensively discuss the prominence of MNFs as catalysts and sensors, enabling future renewable energy alternatives and hotspot-equipped nanomaterials. We discuss various strategies adopted to control the morphology of the NF. We subsequently enumerate notable examples of their catalytic and optical applications. Finally, we summarize the advances achieved and highlight the understanding and requirements to effectively overcome the persisting challenges in the design and synthesis protocol of NFs.

Spectral and Modal Tuning of Surface Plasmons in Symmetric Nanocomposite–Metal Configurations

2025-06-18
Vivek Saxena | Plasmonics

Plasmon hybridization and charge transfer plasmon in nanoparticle complex: An equivalent circuit model approach

2025-06-18
NULL AUTHOR_ID | Physical review. A/Physical review, A

Bright-Field Polarimetry of a Single Plasmonic Nanostructure Combining Polarization and Position Modulation Techniques

2025-06-18
Marius Gauchet , Floriane Perrier , Christophe Bonnet +7 more | ACS Photonics

AI-Assisted Plasmonic Coupling Analysis of Spherical Gold Nanoparticles on Substrate

2025-06-18
Valeria D. Babaylova , Vladislav S. Tuchin , N.S. Petrov +4 more | Photonics
A method of electrostatic deposition of CTAB-stabilized gold nanoparticles on a modified APTES and PSS surface was considered. Positively charged gold nanoparticles with a spherical shape were synthesized using a … A method of electrostatic deposition of CTAB-stabilized gold nanoparticles on a modified APTES and PSS surface was considered. Positively charged gold nanoparticles with a spherical shape were synthesized using a one-step synthesis method with a CTAB surfactant and deposited on a negatively charged modified glass substrate surface with an APTES/PSS layer. Depending on the concentration of the gold nanoparticles, the deposition time, and the modification of the substrate, both isolated nanoparticles with a narrow plasmon peak close to the maximum position in solution, and interacting nanoparticles with varying degrees of plasmonic coupling, were obtained. We also present a deep learning approach for rapid, non-contact estimation of relative plasmon coupling (PC) in gold nanoparticles deposited on substrates using simple camera images. To obtain the training dataset, gold nanoparticles were characterized by the intensity of peaks corresponding to plasmonic coupling in the long-wavelength region of the spectrum. A fully connected neural network was trained to regress PC values from color features, minimizing the mean-squared error. The best model, retrained on the full training set, achieved R2 = 0.83, RMSE = 0.007, MSE = 0.086, and MAE = 0.050 on the test dataset.

In Situ Synthesis of Copper Nanoparticles on Biocarbon Sheets for Surface-Enhanced Raman Scattering

2025-06-18
Jianqiang Wei , Zelong Zhou , Junchao Qian +3 more | Nanomaterials
A copper nanoparticles@porous biocarbon substrate was designed for Surface-Enhanced Raman Spectroscopy (SERS) via a simple reduction method. In the detection of three trace antibiotics, the substrate exhibits a very high … A copper nanoparticles@porous biocarbon substrate was designed for Surface-Enhanced Raman Spectroscopy (SERS) via a simple reduction method. In the detection of three trace antibiotics, the substrate exhibits a very high Raman enhancement efficiency. This is partly because the biocarbon is rich in meso-micropores, which can rapidly trap target molecules. On the other hand, the copper nanoparticles embedded on the surface of the carbon sheets generate a large number of plasmonic hotspots, leading to an increase in Raman signal intensity. These results suggest that this substrate has utility for SERS applications in food safety, medicine, and water pollution detection.

Increasing the Structural Chirality of Metal Nanocrystals Created by Circularly Polarized Light via Surface Ligand Engineering

2025-06-17
Tian Qiao , Priyanuj Bordoloi , Anne E. Ashworth +4 more | Small
Abstract Plasmon‐mediated synthesis enables isotropic metal nanocrystal growth with linearly polarized light. This limits the effect of the polarization of incident light during synthesis, and thus restricts the structural chirality … Abstract Plasmon‐mediated synthesis enables isotropic metal nanocrystal growth with linearly polarized light. This limits the effect of the polarization of incident light during synthesis, and thus restricts the structural chirality of nanocrystals produced with circularly polarized light (CPL). This study here demonstrates that surface engineering of initial achiral silver nanorods (AgNRs) can enhance the structural chirality of the resulting nanostructures produced with CPL. Specifically, the surface ligand hexadecyltrimethylammonium bromide (CTAB) stabilizes the lateral (100) facet‐terminated sides of achiral AgNRs and inhibits lateral growth. This surface engineering with achiral ligands results in increased dissymmetry of the nanostructures during the early stages of photo‐growth and leads to the formation of “hook” structures, where silver preferentially deposits near the tips of the nanorods. Upon further CPL illumination, these “hook” structures exhibit a significantly larger dissymmetry in the local electric field enhancement distribution compared to the initial achiral AgNRs. This highly dissymmetric electric field enhancement profile influences subsequent growth, resulting in AgNRs with enhanced structural chirality. Notably, the optical dissymmetry of these chiral nanostructures with g‐factor ≈0.05 is an order of magnitude greater than that reported in previous studies conducted under similar chemical conditions but without surface engineering.

Electrospun polyacrylonitrile film modified with Ag triangle nanoplates as flexible SERS substrates for HBD-2 detection

2025-06-17
Yueming Gao , Guojun Weng , Jian-Jun Li +2 more | Microchimica Acta

Ultrathin Atomically Flat Gold Film for Scanning Tunneling Microscopy and Single-Particle Fluorescence Spectroscopy

2025-06-17
Zhengyi Bian , Eric Gomez , Junjiang Ren +6 more | Langmuir
To enable rear illumination (e.g., TIRF), single-particle fluorescence microscopy, and scanning tunneling microscopy (STM) on the same nanoparticle sample, we investigate the smoothness limit and the thickness limit of template-stripped … To enable rear illumination (e.g., TIRF), single-particle fluorescence microscopy, and scanning tunneling microscopy (STM) on the same nanoparticle sample, we investigate the smoothness limit and the thickness limit of template-stripped gold films made with a simple room-temperature deposition protocol ranging from 1 to 200 pm/s on four common substrates: mica, fused silica, silicon, and quartz. The resulting transparent conductive gold film achieves a thickness as low as 9 nm, absorbance as low as 0.2, and a root-mean-square roughness of 80 pm over a 100 × 100 nm2 area. We further assess whether such gold films enable single-particle characterization by fluorescence imaging and STM imaging on the same sample. Carbon dots, made by a top-down method, with a height as low as 1.0 nm (∼3 layers), can be resolved clearly on the gold film island surfaces by using both atomic force microscopy and STM, and the carbon dot single-particle fluorescence blinking can be measured by confocal microscopy. In this way, both optical and electronic characterization can be enabled on the same sample using a substrate that is relatively easy to make in batches.

Aspect-Ratio-Controlled Excitonic Zeeman Effects in Alkali Tungsten Bronze Nanocrystals Revealed by Magnetic Circular Dichroism Spectroscopy

2025-06-17
Gyorgy Jaics , Aaron Kenny-Wilby , Emily S. Wedde +4 more | Chemistry of Materials

In Situ-Synthesized Gold Nanostructures (<b>issAu</b>) to Minimize Storage Constraints in Sensing Applications

2025-06-17
Jun Jiang Luo , Han Liu , Hao Zou +1 more | ACS Sensors
Nanoscale gold (Au) materials have garnered significant attention in chemical and biological analyses owing to their exceptional properties. However, their practical applications in sensing nanotechnologies are remarkably constrained by the … Nanoscale gold (Au) materials have garnered significant attention in chemical and biological analyses owing to their exceptional properties. However, their practical applications in sensing nanotechnologies are remarkably constrained by the inherent and universal drawbacks of nanomaterials. For instance, the poor stability of nanomaterials during storage substantially compromises the test repeatability and accuracy. To date, the lack of standardized protocols for the synthesis and storage of nanomaterials remains a critical barrier to the widespread applications of nanotechnologies. Without the storage, in situ-synthesized nanomaterials might offer a promising solution to overcome these storage-related challenges. In this perspective, Au nanostructures are classified into two categories: presynthesized Au (psAu) and in situ-synthesized Au nanostructures (issAu), respectively. Differing from psAu, issAu refers to protocols in which the preparation of Au nanostructures is simultaneously coupled with their concurrent functional applications. While extensive research has been conducted on psAu strategies, recent studies over the past decade have increasingly focused on issAu nanostructures. The issAu concept has exhibited boosted sensing responses and enhanced anti-interference in chemical and biological analysis. Moreover, issAu nanostructures work as intriguing signal probes, showing high potential in time-saving operation and improved selectivity and sensitivity. This perspective outlines the formation routes of issAu nanostructures and provides a comprehensive review of their unique properties and sensing applications. Additionally, a detailed comparison between psAu and issAu materials is correspondingly presented, underscoring the transformative potential of issAu nanostructures and inspiring broader applications of the in situ-synthesis concept for other vital nanomaterials.

MOF-Integrated Plasmonic Nanostructures for Ultrasensitive SERS and Fiber-Optic LSPR Sensing: A ZIF-8@Ag Hybrid Platform for Trace-Level Detection

2025-06-16
Nguyen La Ngoc Tran , Do Thao Anh , Ngoc Quang Tran +3 more | ACS Applied Nano Materials

Nonlocal substrate effect on supported silver clusters revealed by lifted plasmon degeneracy

2025-06-16
Kevin R. Oldenburg , K.‐H. Meiwes‐Broer , Ingo Barke | Physical Review Research
Plasmon resonances of supported metal nanostructures are affected by the substrate in an anisotropic way, which gives rise to mode splitting and inhomogeneous energy shifts. We provide experimental evidence that … Plasmon resonances of supported metal nanostructures are affected by the substrate in an anisotropic way, which gives rise to mode splitting and inhomogeneous energy shifts. We provide experimental evidence that the commonly observed and intuitive case of a weaker influence at larger distances to the substrate does not apply to the plasmon mode structure of small, quasispherical particles. Instead, for the latter, we observe that the energy shift induced by a carbon substrate is strongest if the plasmon is excited farthest from the support. This nonlocal behavior results from the plasmon mode geometry in conjunction with carbon-induced symmetry breaking, which is revealed by electron energy loss spectroscopy (EELS) of silver clusters deposited at the rim of a carbon film. Decomposing the experimental maps based on spectra obtained from the boundary element method (BEM) uncovers the full mode structure. These results strongly suggest that some of the persisting literature controversy on plasmon energies of small, spherical nanoparticles is due to unconsidered spectral effects of an anisotropic local environment. Published by the American Physical Society 2025

Study on Surface‐Enhanced Raman Scattering Spectra of Malachite Green on Silver Surface Based on Density Functional Theory

2025-06-16
Fangkui Liang , Jiahao Bai , Haijun Xu +5 more | Journal of Raman Spectroscopy
ABSTRACT Density functional theory (DFT) at the PBE0‐D 3 hybrid functional and 6‐311G + (d,p) basis set levels was employed to optimize the ground state of malachite green (MG). The … ABSTRACT Density functional theory (DFT) at the PBE0‐D 3 hybrid functional and 6‐311G + (d,p) basis set levels was employed to optimize the ground state of malachite green (MG). The optimized MG molecule has a nonplanar structure. The electrical properties and densities were calculated for MG by the natural population analysis (NPA) method at the same level. GaussView and Multiwfn software were used to draw a Fukui function electron density isosurface coloring map and an electrostatic potential coloring map of the MG molecular surface. We found that the region near the two N atoms in MG was most susceptible to an electrophilic reaction. Time‐dependent density functional theory (TD‐DFT) was used to calculate the electronic excitation data of MG and draw the UV–Vis spectrum of MG at the same level. By comparing the experimental UV–Vis spectrum with the calculated UV–Vis spectrum, it was found that the UV–Vis spectrum of MG has three peaks, of which the maximum peak is 616 nm (calculated as 586 nm). The structure of the MG‐Ag 4 complex was optimized by using DFT. The resonance surface‐enhanced Raman scattering (SERS) spectrum excited with 633‐nm laser light was calculated and compared with the experimental results, and there was a high similarity in the characteristic peak positions between them. Further analysis showed that MG combined with the silver plane by the adsorption orientation of one of the N,N‐dimethylaniline skeleton planes was almost perpendicular to the silver plane in SERS detection. One of the N atoms in N,N‐dimethylaniline is combined with Ag and then adsorbed onto the silver substrate to form a special surface‐bound compound.

Au-Ag Bimetallic Nanoparticles for Surface-Enhanced Raman Scattering (SERS) Detection of Food Contaminants: A Review

2025-06-16
Pengpeng Yu , Chaoping Shen , Xifeng Yin +3 more | Foods
Food contaminants, including harmful microbes, pesticide residues, heavy metals and illegal additives, pose significant public health risks. While traditional detection methods are effective, they are often slow and require complex … Food contaminants, including harmful microbes, pesticide residues, heavy metals and illegal additives, pose significant public health risks. While traditional detection methods are effective, they are often slow and require complex equipment, which limits their application in real-time monitoring and rapid response. Surface-enhanced Raman scattering (SERS) technology has gained widespread use in related research due to its hypersensitivity, non-destructibility and molecular fingerprinting capabilities. In recent years, Au-Ag bimetallic nanoparticles (Au-Ag BNPs) have emerged as novel SERS substrates, accelerating advancements in SERS detection technology. Au-Ag BNPs can be classified into Au-Ag alloys, Au-Ag core-shells and Au-Ag aggregates, among which the Au-Ag core-shell structure is more widely applied. This review discusses the types, synthesis methods and practical applications of Au-Ag BNPs in food contaminants. The study aims to provide valuable insights into the development of new Au-Ag BNPs and their effective use in detecting common food contaminants. Additionally, this paper explores the challenges and future prospects of SERS technology based on Au-Ag BNPs for pollutant detection, including the development of functional integrated substrates, advancements in intelligent algorithms and the creation of portable on-site detection platforms. These innovations are designed to streamline the detection process and offer guidance in selecting optimal sensing methods for the on-site detection of specific pollutants.

Chiral Gold Nanoparticles via L or D‐Cysteine Functionalization: Synthesis and Characterization

2025-06-16
Massimo Ranaldi , Miranda Parisi , Chiara Battocchio +7 more | ChemPlusChem
Chirality, the property of objects being non‐superimposable on their mirror image, is critical in natural phenomena and technological applications, particularly molecular interactions and biological processes. The achievement of nanoscale chirality … Chirality, the property of objects being non‐superimposable on their mirror image, is critical in natural phenomena and technological applications, particularly molecular interactions and biological processes. The achievement of nanoscale chirality has led to the development of gold nanoparticles (AuNPs) with transformative potential in sensing and biosensing, which may find applications in theranostics and drug‐contaminated water treatment. This study presents a wet synthesis approach for chiral gold nanoparticles using L or D‐cysteine, a chiral amino acid. The synthesis begins with small gold spheres, then functionalized with L or D‐cysteine, which binds selectively to kink sites, inducing a twisted shape. These functionalized AuNPs inherit chiral properties, enabling selective interactions with biomolecules, enhancing sensitivity and specificity for detecting enantiomers and biomarkers. Microscopy revealed the twisted shape, dynamic light scattering (DLS) confirmed stability over months, X‐ray photoelectron spectroscopy (XPS) and Fourier‐transform infrared spectroscopy (FT‐IR) validated successful cysteine functionalization and finally, circular dichroism (CD) spectroscopy confirmed optical activity in correspondence of both the molecular absorption and the NP surface plasmon resonance. These optically active AuNPs demonstrate significant promise for molecular diagnostics and environmental sensing, offering new frontiers in biomedical and environmental applications.

A SERS Substrate Based on Ultrasonic Stacking of Nanopowders on Thermoplastics

2025-06-16
Mert Kerem Ulku , Ayşen Gümüştaş , Uğur Tamer +2 more | Journal of Raman Spectroscopy
ABSTRACT Surface‐enhanced Raman spectroscopy (SERS) is often considered as a versatile tool for high‐sensitive detection of low concentrations of analytes. Typically, gold or silver patterned surfaces, namely the SERS substrates, … ABSTRACT Surface‐enhanced Raman spectroscopy (SERS) is often considered as a versatile tool for high‐sensitive detection of low concentrations of analytes. Typically, gold or silver patterned surfaces, namely the SERS substrates, are utilized to amplify Raman signal. However, most SERS substrates require microfabrication processes based on costly infrastructures. In this paper, we propose a simple yet effective scheme for fabricating SERS substrates on thermoplastics. The process involves ultrasonically stacking nanopowders on thermoplastic substrate via a stencil. We showed that gold surfaces on polymethly methacrylate (PMMA) substrates could be fabricated by ultrasonic means in less than 10 s by using a benchtop ultrasonic welder. We investigated the effect of process parameters, namely the pressure and the vibration time, on the surface topography and SERS performance. The results show that the process is mainly controlled by the vibration time, such that at moderate vibration times (~ 5 s), uniformly rough surfaces could be repeatably achieved. Fabricated samples were tested for SERS performance using 5,5′‐ditiobis (2‐nitrobenzoic acid) (DTNB) as the Raman reporter. We showed that the substrates fabricated under 2.7 MPa pressure and 5 s vibration time yielded comparatively low relative standard deviations (RSD) of SERS intensity—6.12% for point‐to‐point variation and 6.73% for batch‐to‐batch variation—along with an enhancement factor (EF) of 1.28 × 10 5 . The performance of the SERS substrates, considering RSD and EF, indicates that the proposed fabrication method could be a promising alternative for SERS based sensing applications.