251
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Valsesia A, Mannelli I, Colpo P, Bretagnol F, Rossi F. Protein Nanopatterns for Improved Immunodetection Sensitivity. Anal Chem 2008; 80:7336-40. [DOI: 10.1021/ac801021z] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- A. Valsesia
- European Commission, Joint Research Centre, Institute for Health and Consumer Protection, 21020 Ispra (VA), Italy
| | - I. Mannelli
- European Commission, Joint Research Centre, Institute for Health and Consumer Protection, 21020 Ispra (VA), Italy
| | - P. Colpo
- European Commission, Joint Research Centre, Institute for Health and Consumer Protection, 21020 Ispra (VA), Italy
| | - F. Bretagnol
- European Commission, Joint Research Centre, Institute for Health and Consumer Protection, 21020 Ispra (VA), Italy
| | - F. Rossi
- European Commission, Joint Research Centre, Institute for Health and Consumer Protection, 21020 Ispra (VA), Italy
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252
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Griffin J, Ray PC. Gold nanoparticle based NSET for monitoring Mg2+ dependent RNA folding. J Phys Chem B 2008; 112:11198-201. [PMID: 18702540 DOI: 10.1021/jp8059322] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Understanding the mechanism of how RNA molecules fold into their native structures are vital to their functional properties. Here we report for the first time that gold nanoparticle based NSET can be used for probing the transition states of an RNA unfolding reaction. Our result shows that time-dependent NSET can clearly distinguish structural transitions between unfolded to folded states. Our experimental observation point out that NSET can be used for the design of an optical based molecular ruler to track RNA folding transition states at distances more than double the distances achievable using traditional dipole-dipole Coulombic energy transfer based methods.
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Affiliation(s)
- Jelani Griffin
- Department of Chemistry, Jackson State University, Jackson, Mississippi 39217-0510, USA
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253
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Khatri OP, Adachi K, Murase K, Okazaki KI, Torimoto T, Tanaka N, Kuwabata S, Sugimura H. Self-assembly of ionic liquid (BMI-PF6)-stabilized gold nanoparticles on a silicon surface: chemical and structural aspects. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:7785-92. [PMID: 18572958 DOI: 10.1021/la800678m] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Ultrafine monodisperse gold nanoparticles (AuNPs) were synthesized by an elegant sputtering of gold onto 1- n-butyl-3-methylimidazolium hexafluorophosphate (BMI-PF(6)) ionic liquid. It was found that the BMI-PF(6) supramolecular aggregates were loosely coordinated to the gold nanoparticles and were replaceable with thiol molecules. The self-assembly of BMI-PF(6)-stabilized AuNPs onto a (3-mercaptopropyl)trimethoxysilane (MPS)-functionalized silicon surface in 2D arrays, followed by dodecanethiol (DDT) treatment, have been demonstrated using X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and contact angle measurements. DDT treatment of tethered AuNPs revealed two types of interactions between AuNPs and the MPS-functionalized surface: (a) AuNPs anchor through Au-S chemisorption linkage resulting in strong immobilization and (b) some of the AuNPs are supported by physisorption, driven by BMI-PF(6). The attachment of these particles remains unchanged with sonication. The replacement of BMI-PF(6) aggregates from physisorbed AuNPs with DDT molecules advances the dilution of their interaction with the MPS-functionalized surface, and they subsequently detach from the silicon surface. The present finding is promising for the immobilization of ionic liquid-stabilized nanoparticles, which is very desirable for electronic and catalytic device fabrication. Additionally, these environmentally friendly AuNPs are expected to replace conventional citrate-stabilized AuNPs.
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Affiliation(s)
- Om P Khatri
- Department of Materials Science and Engineering, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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254
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Buecker P, Trileva E, Himmelhaus M, Dahint R. Label-free biosensors based on optically responsive nanocomposite layers: sensitivity and dynamic range. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:8229-8239. [PMID: 18572887 DOI: 10.1021/la8003883] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Core-shell nanoparticle layers have proven to be a promising tool for the label-free detection of binding events. Upon reflection of white light, they exhibit pronounced extinction peaks in the UV/vis and NIR regime of the electromagnetic spectrum, which shift to higher wavelengths when molecules are adsorbed. Beside drastic simplification of the instrumentation and related reduction in cost, a significantly stronger response toward alkanethiol adsorption has been observed in previous experiments than in conventional surface plasmon resonance (SPR). However, as the amount of molecules deposited onto the nanoparticle films was unknown, no quantitative relationship could be established between the measured wavelength shifts and the surface mass density of the adsorbate. In order to facilitate quantitative molecule detection, self-assembled monolayers (SAMs) of simple and ethylene glycol (EG) terminated alkanethiols with various chain lengths were prepared on the nanoparticle-coated substrates. The measured red-shift of the extinction spectrum upon molecule adsorption was related to the amount of adsorbate as determined by X-ray photoelectron spectroscopy (XPS). For the whole range of film thicknesses studied, a linear relationship is found yielding a sensitivity factor of 0.027 nm/(ng/cm (2)). As proven by enzyme-linked immunosorbent assay (ELISA), such determined sensitivity factor can also be used to correctly predict the amount of surface-bound protein in immunoreactions from the measured wavelength shifts. It is concluded that the decay length of the evanescent electric field associated with the nanoparticle sensors is more than 100 nm and, thus, significantly larger than that observed for localized surface plasmons excited in small isolated metal clusters.
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Affiliation(s)
- P Buecker
- Applied Physical Chemistry, University of Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
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255
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Koenig GM, Gettelfinger BT, de Pablo JJ, Abbott NL. Using localized surface plasmon resonances to probe the nanoscopic origins of adsorbate-driven ordering transitions of liquid crystals in contact with chemically functionalized gold nanodots. NANO LETTERS 2008; 8:2362-2368. [PMID: 18578554 DOI: 10.1021/nl801180c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We report that localized surface plasmon resonances (LSPRs) of gold nanodots immersed under liquid crystals (LCs) can be used to characterize adsorbate-induced ordering transitions of the LCs on the surfaces of the nanodots. The nanoscopic changes in ordering of the LCs, as measured by LSPR, were shown to give rise to macroscopic ordering transitions of the LCs that were observed by polarized light microscopy. The results reported herein suggest that (i) LCs may be useful for enhancing the sensitivity of LSPR-based detection of binding events and (ii) that LSPR measurements of gold nanodots provide a means to characterize the nanoscopic origins of macroscopic, adsorbate-induced LC ordering transitions.
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Affiliation(s)
- Gary M Koenig
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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256
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Abstract
This review focuses on the integration of noble metal nanoparticle aggregates as tags and transport vessels in cellular applications. The natural tendency of nanoparticles to aggregate can be reduced through surface modification; however, this stabilization is often compromised in the cellular environment. The degree of nanoparticle aggregation has both positive and negative consequences. Nanoparticle aggregates are more efficiently removed by the organism compared with single nanoparticles, preventing delivery to their cellular target. In addition, these aggregates are recognized by cells in different ways versus isolated nanoparticles. Despite these negatives, aggregates exhibit enhancement for many detection and treatment techniques in comparison with single nanoparticles. In coming years, the role of aggregates and better control over the degree of aggregation in cellular studies will be required for the realization of medical applications.
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Affiliation(s)
- Maryuri Roca
- University of Iowa, Department of Chemistry, Iowa City IA 52242, USA
| | - Amanda J Haes
- University of Iowa, Department of Chemistry, Iowa City IA 52242, USA
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257
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Directed Synthesis of Micro-Sized Nanoplatelets of Gold from a Chemically Active Mixed Surfactant Mesophase. ADVANCES IN POLYMER SCIENCE 2008. [DOI: 10.1007/12_2008_167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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258
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Anker JN, Hall WP, Lyandres O, Shah NC, Zhao J, Van Duyne RP. Biosensing with plasmonic nanosensors. NATURE MATERIALS 2008; 7:442-53. [PMID: 18497851 DOI: 10.1038/nmat2162] [Citation(s) in RCA: 3113] [Impact Index Per Article: 194.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Recent developments have greatly improved the sensitivity of optical sensors based on metal nanoparticle arrays and single nanoparticles. We introduce the localized surface plasmon resonance (LSPR) sensor and describe how its exquisite sensitivity to size, shape and environment can be harnessed to detect molecular binding events and changes in molecular conformation. We then describe recent progress in three areas representing the most significant challenges: pushing sensitivity towards the single-molecule detection limit, combining LSPR with complementary molecular identification techniques such as surface-enhanced Raman spectroscopy, and practical development of sensors and instrumentation for routine use and high-throughput detection. This review highlights several exceptionally promising research directions and discusses how diverse applications of plasmonic nanoparticles can be integrated in the near future.
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Affiliation(s)
- Jeffrey N Anker
- Chemistry Department, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA
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259
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Sardar R, Bjorge NS, Shumaker-Parry JS. pH-Controlled Assemblies of Polymeric Amine-Stabilized Gold Nanoparticles. Macromolecules 2008. [DOI: 10.1021/ma800407s] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rajesh Sardar
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112
| | - Natalie S. Bjorge
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112
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260
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Chen H, Kou X, Yang Z, Ni W, Wang J. Shape- and size-dependent refractive index sensitivity of gold nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:5233-7. [PMID: 18435552 DOI: 10.1021/la800305j] [Citation(s) in RCA: 616] [Impact Index Per Article: 38.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
Gold nanoparticles of different shapes and sizes, including nanospheres, nanocubes, nanobranches, nanorods, and nanobipyramids, were dispersed into water-glycerol mixtures of varying volume ratios to investigate the response of their surface plasmon peaks to the refractive index of the surrounding medium. The refractive index sensitivities and figures of merit were found to be dependent on both the shape and the size of the Au nanoparticles. The index sensitivities generally increase as Au nanoparticles become elongated and their apexes become sharper. Au nanospheres exhibit the smallest refractive index sensitivity of 44 nm/RIU and Au nanobranches exhibit the largest index sensitivity of 703 nm/RIU. Au nanobipyramids possess the largest figures of merit, which increase from 1.7 to 4.5 as the aspect ratio is increased from 1.5 to 4.7.
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Affiliation(s)
- Huanjun Chen
- Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, P R China
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261
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Langhammer C, Schwind M, Kasemo B, Zorić I. Localized surface plasmon resonances in aluminum nanodisks. NANO LETTERS 2008; 8:1461-1471. [PMID: 18393471 DOI: 10.1021/nl080453i] [Citation(s) in RCA: 215] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The plasmonic properties of arrays of supported Al nanodisks, fabricated by hole-mask colloidal lithography (HCL), are analyzed for the disk diameter range 61-492 nm at a constant disk height of 20 nm. Strong and well-defined (UV-vis-NIR) localized surface plasmon resonances are found and experimentally characterized with respect to spectral peak positions, peak widths, total cross sections, and radiative and nonradiative decay channels. Theoretically, the plasmon excitations are described by electrostatic spheroid theory. Very good qualitative and quantitative agreement between model and experiment is found for all these observables by assuming a nanoparticle embedded in a few nanometer thick homogeneous (native) aluminum oxide shell. Other addressed aspects are: (i) the role of the strong interband transition in Al metal, located at 1.5 eV, for the plasmonic excitations of Al nanoparticles, (ii) the role of the native oxide layer, and (iii) the possibility of using the plasmon excitation as an ultrasensitive, remote, real-time probe for studies of oxidation/corrosion kinetics in metal nanoparticle systems.
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Affiliation(s)
- Christoph Langhammer
- Department of Applied Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden.
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262
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Hall WP, Anker JN, Lin Y, Modica J, Mrksich M, Van Duyne RP. A calcium-modulated plasmonic switch. J Am Chem Soc 2008; 130:5836-7. [PMID: 18402443 DOI: 10.1021/ja7109037] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A plasmonic switch based on the calcium-induced conformational changes of calmodulin is shown to exhibit reversible wavelength modulations in response to changing calcium concentration. The extinction maximum (lambdamax) of a localized surface plasmon resonance (LSPR) sensor functionalized with a novel calmodulin construct, cutinase-calmodulin-cutinase (CutCaMCut), reversibly shifts by 2-3 nm. A high-resolution (HR) LSPR spectrometer with a wavelength resolution (3sigma) of 1.5 x 10-2 nm was developed to detect these wavelength modulations in real-time, providing information about the dynamics and structure of the protein. The rate of conversion from open (Ca2+-bound) to closed (Ca2+-free) calmodulin is shown to be 4-fold faster than the reverse process, with a closing rate of 0.127 s-1 and opening rate of 0.034 s-1. As far as we are aware, this plasmonic switch marks the first use of LSPR spectroscopy to detect reversible conformational changes in an unlabeled protein.
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Affiliation(s)
- W Paige Hall
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA
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263
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Cui B, Clime L, Li K, Veres T. Fabrication of large area nanoprism arrays and their application for surface enhanced Raman spectroscopy. NANOTECHNOLOGY 2008; 19:145302. [PMID: 21817756 DOI: 10.1088/0957-4484/19/14/145302] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This work demonstrates the fabrication of metallic nanoprism (triangular nanostructure) arrays using a low-cost and high-throughput process. In the method, the triangular structure is defined by the shadow of a pyramid during angle evaporation of a metal etching mask. The pyramids were created by nanoimprint lithography in polymethylmethacrylate (PMMA) using a mould having an inverse-pyramid-shaped hole array formed by KOH wet etching of silicon. Silver and gold nanoprism arrays with a period of 200 nm and an edge length of 100 nm have been fabricated and used as effective substrates for surface enhanced Raman spectroscopy (SERS) detection of rhodamine 6G (R6G) molecules. Numerical calculations confirmed the great enhancement of electric field near the sharp nanoprism corners, as well as the detrimental effect of the chromium adhesion layer on localized surface plasmon resonance. The current method can also be used to fabricate non-equilateral nanoprism and three-dimensional (3D) nanopyramid arrays, and it can be readily extended to other metals.
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Affiliation(s)
- B Cui
- Industrial Materials Institute, National Research Council of Canada, 75 de Mortagne Blvd, Boucherville, QC, J4B6Y4, Canada
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264
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265
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Guo L, Nie J, Du B, Peng Z, Tesche B, Kleinermanns K. Thermoresponsive polymer-stabilized silver nanoparticles. J Colloid Interface Sci 2008; 319:175-81. [DOI: 10.1016/j.jcis.2007.11.022] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2007] [Revised: 11/12/2007] [Accepted: 11/19/2007] [Indexed: 11/25/2022]
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266
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Stewart ME, Anderton CR, Thompson LB, Maria J, Gray SK, Rogers JA, Nuzzo RG. Nanostructured Plasmonic Sensors. Chem Rev 2008; 108:494-521. [DOI: 10.1021/cr068126n] [Citation(s) in RCA: 1995] [Impact Index Per Article: 124.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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267
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Choi JS, Choi HJ, Jung DC, Lee JH, Cheon J. Nanoparticle assisted magnetic resonance imaging of the early reversible stages of amyloid β self-assembly. Chem Commun (Camb) 2008:2197-9. [DOI: 10.1039/b803294g] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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268
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Zhang L, Swift J, Butts CA, Yerubandi V, Dmochowski IJ. Structure and activity of apoferritin-stabilized gold nanoparticles. J Inorg Biochem 2007; 101:1719-29. [PMID: 17723241 DOI: 10.1016/j.jinorgbio.2007.07.023] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2007] [Revised: 07/12/2007] [Accepted: 07/13/2007] [Indexed: 11/15/2022]
Abstract
A simple method for synthesizing gold nanoparticles stabilized by horse spleen apoferritin (HSAF) is reported using NaBH(4) or 3-(N-morpholino)propanesulfonic acid (MOPS) as the reducing agent. AuCl(4)(-) reduction by NaBH(4) was complete within a few seconds, whereas reduction by MOPS was much slower; in all cases, protein was required during reduction to keep the gold particles in aqueous solution. Transmission electron microscopy (TEM) showed that the gold nanoparticles were associated with the outer surface of the protein. The average particle diameters were 3.6 and 15.4 nm for NaBH(4)-reduced and MOPS-reduced Au-HSAF, respectively. A 5-nm difference in the UV-Vis absorption maximum was observed for NaBH(4)-reduced (530 nm) and MOPS-reduced Au-HSAF (535 nm), which was attributed to the greater size and aggregation of the MOPS-reduced gold sample. NaBH(4)-reduced Au-HSAF was much more effective than MOPS-reduced Au-HSAF in catalyzing the reduction of 4-nitrophenol by NaBH(4), based on the greater accessibility of the NaBH(4)-reduced gold particle to the substrate. Rapid reduction of AuCl(4)(-) by NaBH(4) was determined to result in less surface passivation by the protein. Methods for studying ferritin-gold nanoparticle assemblies may be readily applied to other protein-metal colloid systems.
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Affiliation(s)
- Lei Zhang
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104-6323, USA
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269
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Chen M, Horn RG. Refractive index of sparse layers of adsorbed gold nanoparticles. J Colloid Interface Sci 2007; 315:814-7. [PMID: 17681511 DOI: 10.1016/j.jcis.2007.06.080] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2007] [Revised: 06/28/2007] [Accepted: 06/29/2007] [Indexed: 12/20/2022]
Abstract
Measurements are presented of the effective complex refractive index of a layer of gold nanoparticles adsorbed to a silicon wafer at low coverages. The measurements were made by means of variable-angle ellipsometry, and correlated with nanoparticle coverage determined from atomic force microscope images. The analysis establishes the effective refractive index of a uniform layer whose thickness equals the nanoparticle diameter. A simple empirical relationship is obtained for real component of refractive index as a function of the fractional nanoparticle coverage regardless of the nanoparticle size. The imaginary component also follows a simple relationship but only up to a certain coverage, above which it increases rapidly. These relationships may be useful in other contexts such as chemical or biosensors in which the nanoparticle coverage could be inferred from optical measurements such as ellipsometry, surface plasmon resonance spectroscopy, reflectometry, or interferometry.
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Affiliation(s)
- Miao Chen
- Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Tianshui Road, Lanzhou 730000, PR China
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270
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Murphy CJ, Gole AM, Hunyadi SE, Stone JW, Sisco PN, Alkilany A, Kinard BE, Hankins P. Chemical sensing and imaging with metallic nanorods. Chem Commun (Camb) 2007:544-57. [PMID: 18209787 DOI: 10.1039/b711069c] [Citation(s) in RCA: 331] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In this Feature Article, we examine recent advances in chemical analyte detection and optical imaging applications using gold and silver nanoparticles, with a primary focus on our own work. Noble metal nanoparticles have exciting physical and chemical properties that are entirely different from the bulk. For chemical sensing and imaging, the optical properties of metallic nanoparticles provide a wide range of opportunities, all of which ultimately arise from the collective oscillations of conduction band electrons ("plasmons") in response to external electromagnetic radiation. Nanorods have multiple plasmon bands compared to nanospheres. We identify four optical sensing and imaging modalities for metallic nanoparticles: (1) aggregation-dependent shifts in plasmon frequency; (2) local refractive index-dependent shifts in plasmon frequency; (3) inelastic (surface-enhanced Raman) light scattering; and (4) elastic (Rayleigh) light scattering. The surface chemistry of the nanoparticles must be tunable to create chemical specificity, and is a key requirement for successful sensing and imaging platforms.
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Affiliation(s)
- Catherine J Murphy
- Department of Chemistry & Biochemistry and the W. M. Keck Laboratory for Bionanoparticle Technology Discovery and Development, University of South Carolina, Columbia, SC 29208, USA.
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271
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Optical organophosphate/phosphonate sensor based upon gold nanoparticle functionalized quartz. Anal Chim Acta 2007; 602:101-7. [DOI: 10.1016/j.aca.2007.08.051] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2007] [Revised: 08/23/2007] [Accepted: 08/31/2007] [Indexed: 11/17/2022]
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272
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Xu Q, Bao J, Capasso F, Whitesides GM. Surface plasmon resonances of free-standing gold nanowires fabricated by nanoskiving. Angew Chem Int Ed Engl 2007; 45:3631-5. [PMID: 16646098 DOI: 10.1002/anie.200600394] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Qiaobing Xu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
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273
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Chen P, Song L, Liu Y, Fang YE. Synthesis of silver nanoparticles by γ-ray irradiation in acetic water solution containing chitosan. Radiat Phys Chem Oxf Engl 1993 2007. [DOI: 10.1016/j.radphyschem.2006.11.012] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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274
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275
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Abstract
The internal field patterns for gold shells filled with the same material as the surrounding medium are calculated with Mie theory and in the quasistatic approximation and their properties compared to the response of homogeneous spheres and metallic rings. One major difference between the sphere and shell case is that the areas of highest field enhancement in metallic shells are located perpendicular to the incident polarization, whereas for metallic spheres they are along the polarization direction. Recent results based on the discrete dipole approximation (DDA) are shown to be misleading, which might be due to the use of a too coarse grid size. We also show that the type of resonance and the associated internal field pattern (low or high energy) has a strong impact on the external fields.
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Affiliation(s)
- Stefan Schelm
- Department of Applied Physics, University of Technology, Sydney, P.O. Box 123 Broadway, 2007 NSW, Australia. stefan.schelm@ uts.edu.au
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276
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Haes AJ, Zhao J, Zou S, Own CS, Marks LD, Schatz GC, Van Duyne RP. Solution-phase, triangular ag nanotriangles fabricated by nanosphere lithography. J Phys Chem B 2007; 109:11158-62. [PMID: 16852361 DOI: 10.1021/jp051178g] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A novel method to produce solution-phase triangular silver nanoparticles is presented. Ag nanoparticles are prepared by nanosphere lithography and are subsequently released into solution. The resulting nanoparticles are asymmetrically functionalized to produce either single isolated nanoparticles or dimer pairs. The structural and optical properties of Ag nanoparticles have been characterized. Mie theory and the Discrete Dipole Approximation method (DDA) have been used to model and interpret the optical properties of the released Ag nanoparticles.
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Affiliation(s)
- Amanda J Haes
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA
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277
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Sánchez DB, Hubenthal F, Träger F. Shaping nanoparticles with laser light: a multi-step approach to produce nanoparticle ensembles with narrow shape and size distributions. ACTA ACUST UNITED AC 2007. [DOI: 10.1088/1742-6596/59/1/051] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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278
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Abstract
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.
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Affiliation(s)
- Katherine A Willets
- Department of Chemistry, Northwestern University, Evanston, IL 60208-3113, USA.
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279
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Cottrell R, McAdory D, Jones J, Gilchrist A, Shields D, Strout DL. Isomer stability and bond-breaking energies of N8C8H8 cages. J Phys Chem A 2007; 110:13889-94. [PMID: 17181349 DOI: 10.1021/jp066032b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Molecules consisting entirely or predominantly of nitrogen have been extensively investigated for their potential as high-energy density materials (HEDM). Such molecules react to produce N2 and large amounts of energy, but many such molecules are too unstable for practical applications. In the present study, cage isomers of N8C8H8 are studied using theoretical calculations to determine the structural features that lead to the most stable cages and determine the energetics of dissociation for the various isomers. The isomers are evaluated for thermodynamic (isomer vs isomer) stability and kinetic (with respect to dissociation) stability. Density functional theory (B3LYP), perturbation theory (MP2), and coupled-cluster theory [CCSD(T)] are employed, in conjunction with the cc-pVDZ basis set of Dunning. Trends in isomer stability and dissociation energies are calculated and discussed.
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Affiliation(s)
- Roshawnda Cottrell
- Department of Biological Sciences, Alabama State University, Montgomery, AL 36101, USA
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280
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Generic surface modification strategy for sensing applications based on Au/SiO2 nanostructures. Biointerphases 2007; 2:49-55. [DOI: 10.1116/1.2717926] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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281
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Quantitative interpretation of gold nanoparticle-based bioassays designed for detection of immunocomplex formation. Biointerphases 2007; 2:6-15. [DOI: 10.1116/1.2700235] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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282
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Qiu JD, Peng HZ, Liang RP, Li J, Xia XH. Synthesis, characterization, and immobilization of Prussian blue-modified Au nanoparticles: application to electrocatalytic reduction of H2O2. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:2133-7. [PMID: 17279705 DOI: 10.1021/la062788q] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Au nanoparticles modified with electroactive Prussian blue (PB) were for the first time synthesized by a simple chemical method. Transmission electronic microscopy showed that the average size of the Prussian blue shell/Au core hybrid composite (PB@Au) was about 50 nm, and Fourier transform IR, UV-vis spectra, and cyclic voltammetry confirmed the existence of PB on the surface of Au nanoparticles. Using the LbL technique, multilayer thin films of PB@Au nanoparticles were prepared by the alternate adsorption of oppositely charged linear polyelectrolyte poly(allylamine hydrochloride) (PAH) onto ITO glass for the construction of a hydrogen peroxide sensor. The novel multilayer films were characterized by SEM, cyclic voltammetry, and UV-visible absorption spectroscopy. The {PAH/PB@Au}n multilayer-modified electrode showed a well-defined pair of redox peaks and dramatic catalytic activity toward the reduction of hydrogen peroxide.
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Affiliation(s)
- Jian-Ding Qiu
- Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China
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283
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Uwada T, Asahi T, Masuhara H, Ibano D, Fujishiro M, Tominaga T. Multipole Resonance Modes in Localized Surface Plasmon of Single Hexagonal/Triangular Gold Nanoplates. CHEM LETT 2007. [DOI: 10.1246/cl.2007.318] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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284
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285
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Isse AA, Gottardello S, Maccato C, Gennaro A. Silver nanoparticles deposited on glassy carbon. Electrocatalytic activity for reduction of benzyl chloride. Electrochem commun 2006. [DOI: 10.1016/j.elecom.2006.08.001] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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286
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Sherry LJ, Jin R, Mirkin CA, Schatz GC, Van Duyne RP. Localized surface plasmon resonance spectroscopy of single silver triangular nanoprisms. NANO LETTERS 2006; 6:2060-5. [PMID: 16968025 DOI: 10.1021/nl061286u] [Citation(s) in RCA: 404] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The plasmonic properties of single silver triangular nanoprisms are investigated using dark-field optical microscopy and spectroscopy. Two distinct localized surface plasmon resonances (LSPR) are observed. These are assigned as in-plane dipolar and quadrupolar plasmon excitations using electrodynamic modeling based on the discrete dipole approximation (DDA). The dipole resonance is found to be very intense, and its peak wavelength is extremely sensitive to the height, edge length, and tip sharpness of the triangular nanoprism. In contrast, the intensity of the quadrupole resonance is much weaker relative to the dipole resonance in the single particle spectra than in the ensemble averaged spectrum. Several parameters relevant to the chemical sensing properties of these nanoprisms have been measured. The dependence of the dipole plasmon resonance on the refractive index of the external medium is found to be as high as 205 nm RIU(-1) and the plasmon line width as narrow as approximately 0.17 eV. These data lead to a sensing figure of merit (FOM), the slope of refractive index sensitivity in eV RIU(-1)/line width (eV), as high as 3.3. In addition, the LSPR shift response to alkanethiol chain length was found to be linear with a slope of 4.4 nm per CH2 unit. This is the highest short-range refractive index sensitivity yet measured for a nanoparticle.
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Affiliation(s)
- Leif J Sherry
- Chemistry Department, Northwestern University, Evanston, Illinois 60208-3113, USA
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287
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Shen H, Cheng B, Lu G, Ning T, Guan D, Zhou Y, Chen Z. Enhancement of optical nonlinearity in periodic gold nanoparticle arrays. NANOTECHNOLOGY 2006; 17:4274-4277. [PMID: 21727571 DOI: 10.1088/0957-4484/17/16/045] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Linear and nonlinear optical properties of periodic triangular Au nanoparticle arrays were investigated. We compared the optical nonlinearity of periodic Au nanoparticle arrays with that of the ultra-thin gold film consisting of randomly distributed spheroidal clusters. A pronounced enhancement of the third-order nonlinear optical susceptibility χ((3)) in Au arrays was observed, and the figure of merit, χ((3))/α, of the periodic nanoparticle arrays is one order of magnitude larger than that of the ultra-thin film. Such an enhancement of the optical nonlinearity could be due to the strong local field near the triangular nanoparticles.
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288
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Zhao J, Zhang X, Yonzon CR, Haes AJ, Van Duyne RP. Localized surface plasmon resonance biosensors. Nanomedicine (Lond) 2006; 1:219-28. [PMID: 17716111 DOI: 10.2217/17435889.1.2.219] [Citation(s) in RCA: 395] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In this review, the most recent progress in the development of noble metal nano-optical sensors based on localized surface plasmon resonance (LSPR) spectroscopy is summarized. The sensing principle relies on the LSPR spectral shifts caused by the surrounding dielectric environmental change in a binding event. Nanosphere lithography, an inexpensive and simple nanofabrication technique, has been used to fabricate the nanoparticles as the LSPR sensing platforms. As an example of the biosensing applications, the LSPR detection for a biomarker of Alzheimer’s disease, amyloid-derived diffusable ligands, in human brain extract and cerebrospinal fluid samples is highlighted. Furthermore, the LSPR sensing method can be modified easily and used in a variety of applications. More specifically, a LSPR chip capable of multiplex sensing, a combined electrochemical and LSPR protocol and a fabrication method of solution-phase nanotriangles are presented here.
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Affiliation(s)
- Jing Zhao
- Northwestern University, Department of Chemistry, Evanston, IL 60208-3113, USA
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289
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Takele H, Greve H, Pochstein C, Zaporojtchenko V, Faupel F. Plasmonic properties of Ag nanoclusters in various polymer matrices. NANOTECHNOLOGY 2006; 17:3499-3505. [PMID: 19661595 DOI: 10.1088/0957-4484/17/14/023] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Nanocomposite films containing Ag nanoparticles embedded in a polymer matrix of Teflon AF, poly(methyl methacrylate) (PMMA) and Nylon 6 were prepared by vapour phase co-deposition in high vacuum. A large variation of the particle plasmon resonance frequency in the visible region was obtained by increasing the Ag volume fraction from 4-80%. The metal volume fraction was measured by energy dispersive x-ray spectrometry (EDX) and the film thickness was measured by surface profilometry. The position, width and strength of the plasmon resonance depend strongly on the metal filling factor, cluster size and interparticle distance. The microstructure of the nanocomposites (shape, size, size distribution and interparticle separation of metal clusters) was determined by transmission electron microscopy. The effect of the surrounding dielectric medium on the optical properties of nanocomposites was investigated by comparing the Teflon AF/Ag, PMMA/Ag and Nylon/Ag composites.
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Affiliation(s)
- H Takele
- Lehrstuhl für Materialverbunde, Technische Fakultät der CAU, Kaiserstrasse 2, D-24143 Kiel, Germany
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290
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Doron-Mor I, Cohen H, Barkay Z, Shanzer A, Vaskevich A, Rubinstein I. Sensitivity of transmission surface plasmon resonance (T-SPR) spectroscopy: self-assembled multilayers on evaporated gold island films. Chemistry 2006; 11:5555-62. [PMID: 16007692 DOI: 10.1002/chem.200500103] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The distance dependence of the localized surface plasmon (SP) extinction of discontinuous gold films is a crucial issue in the application of transmission surface plasmon resonance (T-SPR) spectroscopy to chemical and biological sensing. This derives from the usual sensing configuration, whereby an analyte binds to a selective receptor layer on the gold film at a certain distance from the metal surface. In the present work the distance sensitivity of T-SPR spectroscopy of 1.0-5.0 nm (nominal thickness) gold island films evaporated on silanized glass substrates is studied by using coordination-based self-assembled multilayers, offering thickness tuning in the range from approximately 1 to approximately 15 nm. The morphology, composition and optical properties of the Au/multilayer systems were studied at each step of multilayer construction. High-resolution scanning electron microscopy (HRSEM) showed no apparent change in the underlying Au islands, while atomic force microscopy (AFM) indicated flattening of the surface topography during multilayer construction. A regular growth mode of the organic layers was substantiated by X-ray photoelectron spectroscopy (XPS). Transmission UV-visible spectra showed an increase of the extinction and a red shift of the maximum of the SP band upon addition of organic layers, establishing the distance dependence of the Au SP absorbance. The distance sensitivity of T-SPR spectroscopy can be varied by using characteristic substrate parameters, that is, Au nominal thickness and annealing. In particular, effective sensitivity up to a distance of at least 15 nm is demonstrated with 5 nm annealed Au films. It is shown that intensity measurements, particularly in the plasmon intensity change (PIC) presentation, provide an alternative to the usually measured plasmon band position, offering good accuracy and the possibility of measuring at a single wavelength. The present distance sensitivity results provide the basis for further development of T-SPR transducers based on receptor-coated Au island films.
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Affiliation(s)
- Ilanit Doron-Mor
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
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291
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Zou S, Schatz GC. Narrow plasmonic/photonic extinction and scattering line shapes for one and two dimensional silver nanoparticle arrays. J Chem Phys 2006; 121:12606-12. [PMID: 15606284 DOI: 10.1063/1.1826036] [Citation(s) in RCA: 283] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The interaction of light with silver nanoparticle arrays can in some cases produce mixed plasmonic/photonic bands that have extremely narrow (<1 meV) line shapes in extinction and scattering. In this paper we extend computational electrodynamics results of a recent communication [S. Zou, N. Janel, and G. C. Schatz, J. Chem. Phys. 120, 10871 (2004)] where this effect was first described to study how these narrow bands are influenced by a number of structural factors, and to determine how useful these arrays might be for sensing applications. Included are studies of the effect of disorder in the array structure on plasmon intensity and width, of the effect of orientation of the array relative to the polarization and propagation direction of the incident light, and of the effect of particle shape (comparing results for silver spheres and cylindrical disks). Our results show that the narrow lines are remarkably robust to array disorder, but vacancy defects can easily destroy the effect. The narrowest lines are associated with one dimensional arrays in which both polarization and wave vectors are perpendicular to the array axis. For two dimensional arrays, the narrowest lines are associated with the wave vector perpendicular to the plane of the array and polarization in the plane. Arrays composed of oblate cylinders generate more intense and more redshifted plasmon/photonic peaks than do prolate or spherical particles under comparable conditions. Finally, for sensing applications in which analyte binding is determined by the plasmon wavelength shift associated with change in the surface refractive index, we show that the arrays have greater sensitivity than isolated nanoparticles.
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Affiliation(s)
- Shengli Zou
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, USA
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292
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Xu Q, Bao J, Capasso F, Whitesides GM. Surface Plasmon Resonances of Free-Standing Gold Nanowires Fabricated by Nanoskiving. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200600394] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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293
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Chen CD, Cheng SF, Chau LK, Wang CRC. Sensing capability of the localized surface plasmon resonance of gold nanorods. Biosens Bioelectron 2006; 22:926-32. [PMID: 16697633 DOI: 10.1016/j.bios.2006.03.021] [Citation(s) in RCA: 182] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Revised: 03/18/2006] [Accepted: 03/22/2006] [Indexed: 10/24/2022]
Abstract
We demonstrate the feasibility of using the longitudinal component of gold nanorod's surface plasmon resonance in biomolecular sensing. The sensitive dependence of the absorption maximum on the dielectric constant of the particle interfacial region makes gold nanorods a promise for constructing a biomolecular sensing scheme. The sensor containing gold nanorods, with a mean aspect ratio of 5.2, exhibits a sensitivity of ca. 366 nm/RIU (refractive index unit), which increases accordingly with the increase of the particle mean aspect ratios. Such a biosensor was further modified to demonstrate its effectiveness in quantitative detection for selective binding events, such as biotin/streptavidin pairs, through a process in which biotin molecules were chemically attached to the gold nanorods' surface prior to detection measurements. Results showed that the spectral lambda(max) shifts linearly to the concentrations of the streptavidin. The results from both experiment and model calculations strongly indicate the efficacy of the longitudinal surface plasmon absorption band in biosensing.
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Affiliation(s)
- Cheng-Dah Chen
- Department of Chemistry and Biochemistry, National Chung Cheng University, 168 University Road, Min-Hsiung, Chia-Yi 621, Taiwan
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294
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Miller MM, Lazarides AA. Sensitivity of metal nanoparticle plasmon resonance band position to the dielectric environment as observed in scattering. ACTA ACUST UNITED AC 2006. [DOI: 10.1088/1464-4258/8/4/s26] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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295
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Zhang X, Yonzon CR, Young MA, Stuart DA, Van Duyne RP. Surface-enhanced Raman spectroscopy biosensors: excitation spectroscopy for optimisation of substrates fabricated by nanosphere lithography. ACTA ACUST UNITED AC 2006; 152:195-206. [PMID: 16441180 DOI: 10.1049/ip-nbt:20050009] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In the 28 years since its discovery, surface-enhanced Raman scattering (SERS) has progressed from model system studies of pyridine on a roughened silver electrode to state-of-the-art surface science studies and real-world sensing applications. Each year, the number of SERS publications increases as nanoscale material design techniques advance and the importance of trace analyte detection increases. To achieve the lowest limits of detection, both the relationship between surface nanostructure and laser excitation wavelength and the analyte-surface binding chemistry must be carefully optimised. This work exploits the highly tunable nature of nanoparticle optical properties to establish the optimisation conditions. Two methods are used to study the optimised conditions of the SERS substrate: plasmon-sampled and wavelength-scanned surfaced Raman excitation spectroscopy (SERES). The SERS enhancement condition is optimised when the energy of the localised surface plasmon resonance of the nanostructures lies between the energy of the excitation wavelength and the energy of the vibration band of interest. These optimised conditions enabled the development of SERS-based sensors for the detection of a Bacillus anthracis biomarker and glucose in a serum-protein matrix.
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Affiliation(s)
- X Zhang
- Department of Chemistry, Northwestern University, Evanston, IL 60201, USA
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296
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Kan C, Zhu X, Wang G. Single-Crystalline Gold Microplates: Synthesis, Characterization, and Thermal Stability. J Phys Chem B 2006; 110:4651-6. [PMID: 16526697 DOI: 10.1021/jp054800d] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Single-crystalline gold microplates of several 10 microm in lateral size, characterized by hexagonal, truncated triangular, and triangular shapes with (111) planes as two basal surfaces, have been synthesized in large quantities through a solution phase process. Significantly, such anisotropic Au nanostructures exhibit remarkable optical properties, in which the dipole plasmon resonance shifting in the NIR region and the quadrupole plasmon resonance at approximately 820 nm were observed. Fragmentation of Au microplates is found when the temperature is higher than 450 degrees C, indicating they are not thermodynamically stable structure at high temperature. Investigations on the Au microplates upon heating suggest that the melting and collapsing start mainly at the edges that should be Au (110) facets. This work is valuable for Au nanostructures applied at elevated temperatures.
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Affiliation(s)
- Caixia Kan
- National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing, 210093, PR China.
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297
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Dieringer JA, McFarland AD, Shah NC, Stuart DA, Whitney AV, Yonzon CR, Young MA, Zhang X, Van Duyne RP. Introductory Lecture : Surface enhanced Raman spectroscopy: new materials, concepts, characterization tools, and applications. Faraday Discuss 2006; 132:9-26. [PMID: 16833104 DOI: 10.1039/b513431p] [Citation(s) in RCA: 304] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Surface-enhanced Raman spectroscopy (SERS) is currently experiencing a renaissance in its development driven by the remarkable discovery of single molecule SERS (SMSERS) and the explosion of interest in nanophotonics and plasmonics. Because excitation of the localized surface plasmon resonance (LSPR) of a nanostructured surface or nanoparticle lies at the heart of SERS, it is important to control all of the factors influencing the LSPR in order to maximize signal strength and ensure reproducibility. These factors include material, size, shape, interparticle spacing, and dielectric environment. All of these factors must be carefully controlled to ensure that the incident laser light maximally excites the LSPR in a reproducible manner. This article describes the use of nanosphere lithography for the fabrication of highly reproducible and robust SERS substrates for both fundamental studies and applications. Atomic layer deposition (ALD) is introduced as a novel fabrication method for dielectric spacers to study the SERS distance dependence and control the nanoscale dielectric environment. Wavelength scanned SER excitation spectroscopy (WS SERES) measurements show that enhancement factors approximately 10(8) are obtainable from NSL-fabricated surfaces and provide new insight into the electromagneticfield enhancement mechanism. Tip-enhanced Raman spectroscopy (TERS) is an extremely promising new development to improve the generality and information content of SERS. A 2D correlation analysis is applied to SMSERS data. Finally, the first in vivo SERS glucose sensing study is presented.
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Affiliation(s)
- Jon A Dieringer
- Department of Chemistry, Northwestern University, Evanston IL 60208-3113, USA
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298
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Hicks EM, Zhang X, Zou S, Lyandres O, Spears KG, Schatz GC, Van Duyne RP. Plasmonic Properties of Film over Nanowell Surfaces Fabricated by Nanosphere Lithography. J Phys Chem B 2005; 109:22351-8. [PMID: 16853911 DOI: 10.1021/jp0545400] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this work, a detailed and systematic study of the plasmonic properties of a novel film over nanowell surface is investigated. These nanostructures are fabricated using nanosphere lithography and reactive ion etching and structurally characterized by AFM and SEM. The resulting structures show remarkably narrow plasmon bands in reflectance spectra (as little as 0.10 eV) and greater sensitivity to external dielectric environment than has been seen in other nanoparticle systems, resulting in an improvement in the figure of merit (FOM = refractive index sensitivity (eV.RIU(-1))/full width at half-maximum (eV)) for refractive index sensing. Theoretical modeling for the plasmon spectra of these nanostructures is done using discrete dipole approximation code under periodic boundary conditions. The modeling results match the measurements accurately in aspects of the variation of the plasmon line shape with altering internanowell distance and dielectric environment.
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Affiliation(s)
- Erin M Hicks
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA
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299
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Katz E, Willner I. Integrated nanoparticle-biomolecule hybrid systems: synthesis, properties, and applications. Angew Chem Int Ed Engl 2005; 43:6042-108. [PMID: 15538757 DOI: 10.1002/anie.200400651] [Citation(s) in RCA: 1631] [Impact Index Per Article: 85.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Nanomaterials, such as metal or semiconductor nanoparticles and nanorods, exhibit similar dimensions to those of biomolecules, such as proteins (enzymes, antigens, antibodies) or DNA. The integration of nanoparticles, which exhibit unique electronic, photonic, and catalytic properties, with biomaterials, which display unique recognition, catalytic, and inhibition properties, yields novel hybrid nanobiomaterials of synergetic properties and functions. This review describes recent advances in the synthesis of biomolecule-nanoparticle/nanorod hybrid systems and the application of such assemblies in the generation of 2D and 3D ordered structures in solutions and on surfaces. Particular emphasis is directed to the use of biomolecule-nanoparticle (metallic or semiconductive) assemblies for bioanalytical applications and for the fabrication of bioelectronic devices.
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Affiliation(s)
- Eugenii Katz
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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300
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Mitchell JS, Wu Y, Cook CJ, Main L. Sensitivity enhancement of surface plasmon resonance biosensing of small molecules. Anal Biochem 2005; 343:125-35. [PMID: 15950915 DOI: 10.1016/j.ab.2005.05.001] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2005] [Revised: 04/29/2005] [Accepted: 05/02/2005] [Indexed: 11/24/2022]
Abstract
Surface plasmon resonance (SPR) biosensor formats using gold nanoparticle or protein signal amplification for the sensitive assay of small molecules were developed using progesterone as a model compound. Progesterone was immobilized to a dextran surface in the Biacore biosensor through in situ covalent immobilization using an oligoethylene glycol linker attached to the 4 position of the steroid. This surface produced stable antibody binding for in excess of 1100 assay cycles. Using this surface, assays were developed for progesterone using 10- and 20-nm gold-streptavidin labels attached to biotinylated monoclonal antibody in both label prebinding and sequential binding formats. Prelabeling formats gave no signal enhancement but produced assays with limits of detection of 143 pg/ml, compared with approximately 1 ng/ml in previous studies. Sequential binding formats gave signal enhancements of 2.2-fold over the monoclonal antibody and a limit of detection of 23.1 pg/ml. It was found that secondary antibody labeling gave 8.1-fold signal enhancements and a limit of detection of 20.1 pg/ml, whereas use of secondary antibody-25 nm gold complexes provided more signal enhancement (13-fold) and a further improvement in limit of detection of 8.6 pg/ml.
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Affiliation(s)
- John S Mitchell
- Bioengineering Sector, HortResearch, Private Bag 3123, Hamilton, New Zealand
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