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Zavatski S, Dubkov S, Gromov D, Bandarenka H. Comparative Study of SERS-Spectra of NQ21 Peptide on Silver Particles and in Gold-Coated "Nanovoids". BIOSENSORS 2023; 13:895. [PMID: 37754129 PMCID: PMC10526949 DOI: 10.3390/bios13090895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 08/21/2023] [Accepted: 09/18/2023] [Indexed: 09/28/2023]
Abstract
The NQ21 peptide has relatively recently attracted attention in the biomedical sphere due to its prospects for facilitating the engineering of the HIV1 vaccine and ELISA test. Today, there is still a need for a reliable and fast methodology that reveals the secondary structure of this analyte at the low concentrations conventionally used in vaccines and immunological assays. The present research determined the differences between the surface-enhanced Raman scattering (SERS) spectra of NQ21 peptide molecules adsorbed on solid SERS-active substrates depending on their geometry and composition. The ultimate goal of our research was to propose an algorithm and SERS-active material for structural analysis of peptides. Phosphate buffer solutions of the 30 µg/mL NQ21 peptide at different pH levels were used for the SERS measurements, with silver particles on mesoporous silicon and gold-coated "nanovoids" in macroporous silicon. The SERS analysis of the NQ21 peptide was carried out by collecting the SERS spectra maps. The map assessment with an originally developed algorithm resulted in defining the effect of the substrate on the secondary structure of the analyte molecules. Silver particles are recommended for peptide detection if it is not urgent to precisely reveal all the characteristic bands, because they provide greater enhancement but are accompanied by analyte destruction. If the goal is to carefully study the secondary structure and composition of the peptide, it is better to use SERS-active gold-coated "nanovoids". Objective results can be obtained by collecting at least three 15 × 15 maps of the SERS spectra of a given peptide on substrates from different batches.
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Affiliation(s)
- Siarhei Zavatski
- Applied Plasmonic Laboratory, Belarusian State University of Informatics and Radioelectronics, 220013 Minsk, Belarus;
| | - Sergey Dubkov
- Institute of Advanced Materials and Technologies, National Research University of Electronic Technology, Moscow 124498, Russia; (S.D.)
| | - Dmitry Gromov
- Institute of Advanced Materials and Technologies, National Research University of Electronic Technology, Moscow 124498, Russia; (S.D.)
- Institute for Bionic Technologies and Engineering, I.M. Sechenov First Moscow State Medical University, Moscow 119435, Russia
| | - Hanna Bandarenka
- Applied Plasmonic Laboratory, Belarusian State University of Informatics and Radioelectronics, 220013 Minsk, Belarus;
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Gimenez AV, Kho KW, Keyes TE. Nano-substructured plasmonic pore arrays: a robust, low cost route to reproducible hierarchical structures extended across macroscopic dimensions. NANOSCALE ADVANCES 2020; 2:4740-4756. [PMID: 36132883 PMCID: PMC9417107 DOI: 10.1039/d0na00527d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 08/11/2020] [Indexed: 05/17/2023]
Abstract
Plasmonic nanostructures are important across diverse applications from sensing to renewable energy. Periodic porous array structures are particularly attractive because such topography offers a means to encapsulate or capture solution phase species and combines both propagating and localised plasmonic modes offering versatile addressability. However, in analytical spectroscopic applications, periodic pore arrays have typically reported weaker plasmonic signal enhancement compared to particulate structures. This may be addressed by introducing additional nano-structuring into the array to promote plasmonic coupling that promotes electric field-enhancement, whilst retaining pore structure. Introducing nanoparticle structures into the pores is a useful means to promote such coupling. However, current approaches rely on either expensive top-down methods or on bottom-up methods that yield random particle placement and distribution. This report describes a low cost, top-down technique for preparation of nano-sub-structured plasmonic pore arrays in a highly reproducible manner that can be applied to build arrays extending over macroscopic areas of mm2 to cm2. The method exploits oxygen plasma etching, under controlled conditions, of the cavity encapsulated templating polystyrene (PS) spheres used to create the periodic array. Subsequent metal deposition leads to reproducible nano-structuring within the wells of the pore array, coined in-cavity nanoparticles (icNPs). This approach was demonstrated across periodic arrays with pore/sphere diameters ranging from 500 nm to 3 μm and reliably improved the plasmonic properties of the substrate across all array dimensions compared to analogous periodic arrays without the nano-structuring. The enhancement factors achieved for metal enhanced emission and surface enhanced Raman spectroscopy depended on the substrate dimensions, with the best performance achieved for nanostructured 2 μm diameter pore arrays, where a more than 104 improvement over Surface Enhanced Raman Spectroscopy (SERS) and 200-fold improvement over Metal Enhanced Fluorescence (MEF) were observed for these substrates compared with analogous unmodified pore arrays. The experiments were supported by Finite-Difference Time-Domain (FDTD) calculations used to simulate the electric field distribution as a function of pore nano-structuring.
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Affiliation(s)
- Aurélien V Gimenez
- School of Chemical Sciences & National Centre for Sensor Research, Dublin City University Dublin 9 Ireland
| | - Kiang W Kho
- School of Chemical Sciences & National Centre for Sensor Research, Dublin City University Dublin 9 Ireland
| | - Tia E Keyes
- School of Chemical Sciences & National Centre for Sensor Research, Dublin City University Dublin 9 Ireland
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3
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Wang L, Wang Z, Li L, Zhang J, Liu J, Hu J, Wu X, Weng Z, Chu X, Li J, Qiao Z. Magnetic-plasmonic Ni@Au core-shell nanoparticle arrays and their SERS properties. RSC Adv 2020; 10:2661-2669. [PMID: 35496119 PMCID: PMC9048804 DOI: 10.1039/c9ra10354f] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 01/08/2020] [Indexed: 12/20/2022] Open
Abstract
In this paper, large-area magnetic-plasmonic Ni@Au core-shell nanoparticle arrays (NPAs) with tunable compositions were successfully fabricated by a direct laser interference ablation (DLIA) incorporated with thermal dewetting method. The magnetic properties of the Ni@Au core-shell NPAs were analyzed and the saturation magnetization (M s) of the Ni80@Au20 nanoparticles was found to be higher than that of nickel-only nanoparticles with the same diameter. Using Rhodamine 6G (R6G) as a Raman reporter molecule, the surface enhanced Raman scattering (SERS) property of the Ni@Au core-shell NPAs with a grain size distribution of 48 ± 42 nm and a short-distance order of about 200 nm was examined. A SERS enhancement factor of 2.5 × 106 was realized on the Ni50@Au50 NPA substrate, which was 9 times higher than that for Au nanoparticles with the same size distribution. This was due to the enhanced local surface plasmon resonance (LSPR) between the ferromagnetic Ni cores and the surface polariton of the Au shells of each nanoparticle. The fabrication of the Ni@Au core-shell NPAs with different compositions offers a new avenue to tailor the optical and magnetic properties of the nanostructured films for chemical and diagnostic applications.
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Affiliation(s)
- Lu Wang
- International Research Centre for Nano Handling and Manufacturing of China, Changchun University of Science and Technology Changchun 130022 China +86 431 85582925 +86 431 85582926
- Ministry of Education Key Laboratory for Cross-Scale Micro and Nano Manufacturing, Changchun University of Science and Technology Changchun 130022 China
| | - Zuobin Wang
- International Research Centre for Nano Handling and Manufacturing of China, Changchun University of Science and Technology Changchun 130022 China +86 431 85582925 +86 431 85582926
- Ministry of Education Key Laboratory for Cross-Scale Micro and Nano Manufacturing, Changchun University of Science and Technology Changchun 130022 China
| | - Li Li
- International Research Centre for Nano Handling and Manufacturing of China, Changchun University of Science and Technology Changchun 130022 China +86 431 85582925 +86 431 85582926
- Ministry of Education Key Laboratory for Cross-Scale Micro and Nano Manufacturing, Changchun University of Science and Technology Changchun 130022 China
| | - Jingran Zhang
- International Research Centre for Nano Handling and Manufacturing of China, Changchun University of Science and Technology Changchun 130022 China +86 431 85582925 +86 431 85582926
| | - Jinyun Liu
- College of Information Engineering, North China University of Science and Technology Tangshan 063210 China
| | - Jing Hu
- International Research Centre for Nano Handling and Manufacturing of China, Changchun University of Science and Technology Changchun 130022 China +86 431 85582925 +86 431 85582926
| | - Xiaomin Wu
- International Research Centre for Nano Handling and Manufacturing of China, Changchun University of Science and Technology Changchun 130022 China +86 431 85582925 +86 431 85582926
| | - Zhankun Weng
- International Research Centre for Nano Handling and Manufacturing of China, Changchun University of Science and Technology Changchun 130022 China +86 431 85582925 +86 431 85582926
- Ministry of Education Key Laboratory for Cross-Scale Micro and Nano Manufacturing, Changchun University of Science and Technology Changchun 130022 China
| | - Xueying Chu
- School of Science, Changchun University of Science and Technology Changchun 130022 China
| | - Jinhua Li
- School of Science, Changchun University of Science and Technology Changchun 130022 China
| | - Zhongliang Qiao
- Key Laboratory of Laser Technology and Optoelectronic Functional Materials of Hainan Province, School of Physics and Electronic Engineering, Hainan Normal University Haikou 571158 China +86 898-65861468 +86 898 65861468
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Girel KV, Panarin AY, Bandarenka HV, Isic G, Bondarenko VP, Terekhov SN. Plasmonic silvered nanostructures on macroporous silicon decorated with graphene oxide for SERS-spectroscopy. NANOTECHNOLOGY 2018; 29:395708. [PMID: 29988021 DOI: 10.1088/1361-6528/aad250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A method for fabricating surface-enhanced Raman scattering (SERS)-active substrates by immersion deposition of silver on a macroporous silicon (macro-PS) template with pore diameters and depth ranging from 500-1000 nm is developed. The procedure for the formation of nanostructured silver films in the layers of macro-PS was optimized. Silver particles of dimensions in the nano- and submicron-scale were formed on the external surface of the macro-PS immersed in the water-ethanol solution of AgNO3, while the inner pore walls were covered by smaller, 10-30 nm diameter, silver nanoparticles. Upon introducing the hydrofluoric acid to the reaction mixture, the size of nanoparticles grown on the pore walls increased up to 100-150 nm. Such nanostructures were found to yield SERS-signal intensities from CuTMpyP4 analyte molecules of the same order to those obtained from silvered mesoporous silicon reported previously. The tested storage stability for the silvered macro-PS-based samples reached up to 8 months. However, degradation of the SERS intensity under illumination by the laser beam during spectral measurements was observed. To improve the stability of the SERS-signal a hybrid structure involving graphene oxide deposited on the top of analyte molecules adsorbed on the Ag/macro-PS was formed. A systematic observation of the time evolution of the characteristic peak at 1365 cm-1 showed that the addition of the oxidized graphene layer over the analyte results in ∼2 times slower decay of the Raman intensity, indicating that the graphene coating can be used to enhance the stability of the SERS-signal from the CuTMpyP4 molecules.
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Affiliation(s)
- K V Girel
- Micro- and Nanoelectronics Department of BSUIR, Brovka St., 6, 220013, Minsk, Belarus
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5
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Xu S, Lei Y. Template-Assisted Fabrication of Nanostructured Arrays for Sensing Applications. Chempluschem 2018; 83:741-755. [DOI: 10.1002/cplu.201800127] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 05/08/2018] [Indexed: 01/07/2023]
Affiliation(s)
- Shipu Xu
- Institute of Physics & IMN MacroNano (ZIK); Ilmenau University of Technology; Unterpoerlitzer Strasse 38 98693 Ilmenau Germany
| | - Yong Lei
- Institute of Physics & IMN MacroNano (ZIK); Ilmenau University of Technology; Unterpoerlitzer Strasse 38 98693 Ilmenau Germany
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6
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Mahigir A, Chang TW, Behnam A, Liu GL, Gartia MR, Veronis G. Plasmonic nanohole array for enhancing the SERS signal of a single layer of graphene in water. Sci Rep 2017; 7:14044. [PMID: 29070864 PMCID: PMC5656589 DOI: 10.1038/s41598-017-14369-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 10/09/2017] [Indexed: 11/09/2022] Open
Abstract
We numerically design and experimentally test a SERS-active substrate for enhancing the SERS signal of a single layer of graphene (SLG) in water. The SLG is placed on top of an array of silver-covered nanoholes in a polymer and is covered with water. Here we report a large enhancement of up to 2 × 105 in the SERS signal of the SLG on the patterned plasmonic nanostructure for a 532 nm excitation laser wavelength. We provide a detailed study of the light-graphene interactions by investigating the optical absorption in the SLG, the density of optical states at the location of the SLG, and the extraction efficiency of the SERS signal of the SLG. Our numerical calculations of both the excitation field and the emission rate enhancements support the experimental results. We find that the enhancement is due to the increase in the confinement of electromagnetic fields on the location of the SLG that results in enhanced light absorption in the graphene at the excitation wavelength. We also find that water droplets increase the density of optical radiative states at the location of the SLG, leading to enhanced spontaneous emission rate of graphene at its Raman emission wavelengths.
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Affiliation(s)
- Amirreza Mahigir
- School of Electrical Engineering and Computer Sciences, Louisiana State University, Baton Rouge, Louisiana, 70803, USA.,Center for Computation and Technology, Louisiana State University, Baton Rouge, Louisiana, 70808, USA
| | - Te-Wei Chang
- Intel Corporation, Ronler Acres Campus, Hillsboro, Oregon, 97124, USA
| | - Ashkan Behnam
- Department of Electrical and Computer Engineering, University of Illinois at Urbana Champaign, Urbana, Illinois, 61801, USA
| | - Gang Logan Liu
- Department of Electrical and Computer Engineering, University of Illinois at Urbana Champaign, Urbana, Illinois, 61801, USA
| | - Manas Ranjan Gartia
- Department of Mechanical and Industrial Engineering, Louisiana State University, Baton Rouge, Louisiana, 70803, USA.
| | - Georgios Veronis
- School of Electrical Engineering and Computer Sciences, Louisiana State University, Baton Rouge, Louisiana, 70803, USA. .,Center for Computation and Technology, Louisiana State University, Baton Rouge, Louisiana, 70808, USA.
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7
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Adamson K, Spain E, Prendergast U, Moran N, Forster RJ, Keyes TE. Peptide-Mediated Platelet Capture at Gold Micropore Arrays. ACS APPLIED MATERIALS & INTERFACES 2016; 8:32189-32201. [PMID: 27933817 DOI: 10.1021/acsami.6b11137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Ordered spherical cap gold cavity arrays with 5.4, 1.6, and 0.98 μm diameter apertures were explored as capture surfaces for human blood platelets to investigate the impact of surface geometry and chemical modification on platelet capture efficiency and their potential as platforms for surface enhanced Raman spectroscopy of single platelets. The substrates were chemically modified with single-constituent self-assembled monolayers (SAM) or mixed SAMs comprised of thiol-functionalized arginine-glycine-aspartic acid (RGD, a platelet integrin target) with or without 1-octanethiol (adhesion inhibitor). As expected, platelet adhesion was promoted and inhibited at RGD and alkanethiol modified surfaces, respectively. Platelet adhesion was reversible, and binding efficiency at the peptide modified substrates correlated inversely with pore diameter. Captured platelets underwent morphological change on capture, the extent of which depended on the topology of the underlying substrate. Regioselective capture of the platelets enabled study for the first time of the surface enhanced Raman spectroscopy of single blood platelets, yielding high quality Raman spectroscopy of individual platelets at 1.6 μm diameter pore arrays. Given the medical importance of blood platelets across a range of diseases from cancer to psychiatric illness, such approaches to platelet capture may provide a useful route to Raman spectroscopy for platelet related diagnostics.
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Affiliation(s)
- Kellie Adamson
- School of Chemical Sciences, Dublin City University , Dublin 9, Ireland
| | - Elaine Spain
- School of Chemical Sciences, Dublin City University , Dublin 9, Ireland
| | - Una Prendergast
- School of Chemical Sciences, Dublin City University , Dublin 9, Ireland
| | - Niamh Moran
- Dept. of Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland , Dublin 2, Ireland
| | - Robert J Forster
- School of Chemical Sciences, Dublin City University , Dublin 9, Ireland
| | - Tia E Keyes
- School of Chemical Sciences, Dublin City University , Dublin 9, Ireland
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9
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Jahn M, Patze S, Hidi IJ, Knipper R, Radu AI, Mühlig A, Yüksel S, Peksa V, Weber K, Mayerhöfer T, Cialla-May D, Popp J. Plasmonic nanostructures for surface enhanced spectroscopic methods. Analyst 2016; 141:756-93. [DOI: 10.1039/c5an02057c] [Citation(s) in RCA: 143] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The development within the last five years in the field of surface enhanced spectroscopy methods was comprehensively reviewed.
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10
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Ai B, Yu Y, Möhwald H, Zhang G, Yang B. Plasmonic films based on colloidal lithography. Adv Colloid Interface Sci 2014; 206:5-16. [PMID: 24321859 DOI: 10.1016/j.cis.2013.11.010] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 11/15/2013] [Accepted: 11/15/2013] [Indexed: 10/26/2022]
Abstract
This paper reviews recent advances in the field of plasmonic films fabricated by colloidal lithography. Compared with conventional lithography techniques such as electron beam lithography and focused ion beam lithography, the unconventional colloidal lithography technique with advantages of low-cost and high-throughput has made the fabrication process more efficient, and moreover brought out novel films that show remarkable surface plasmon features. These plasmonic films include those with nanohole arrays, nanovoid arrays and nanoshell arrays with precisely controlled shapes, sizes, and spacing. Based on these novel nanostructures, optical and sensing performances can be greatly enhanced. The introduction of colloidal lithography provides not only efficient fabrication processes but also plasmonic films with unique nanostructures, which are difficult to be fabricated by conventional lithography techniques.
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11
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Zhu X, Shi L, Schmidt MS, Boisen A, Hansen O, Zi J, Xiao S, Mortensen NA. Enhanced light-matter interactions in graphene-covered gold nanovoid arrays. NANO LETTERS 2013; 13:4690-6. [PMID: 24010940 DOI: 10.1021/nl402120t] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The combination of graphene with noble-metal nanostructures is currently being explored for strong light-graphene interactions enhanced by plasmons. We introduce a novel hybrid graphene-metal system for studying light-matter interactions with gold-void nanostructures exhibiting resonances in the visible range. Enhanced coupling of graphene to the plasmon modes of the nanovoid arrays results in significant frequency shifts of the underlying plasmon resonances, enabling 30% enhanced absolute light absorption by adding a monolayer graphene and up to 700-fold enhancement of the Raman response of the graphene. These new perspectives enable us to verify the presence of graphene on gold-void arrays, and the enhancement even allows us to accurately quantify the number of layers. Experimental observations are further supported by numerical simulations and perturbation-theory analysis. The graphene gold-void platform is beneficial for sensing of molecules and placing Rhodamine 6G (R6G) dye molecules on top of the graphene; we observe a strong enhancement of the R6G Raman fingerprints. These results pave the way toward advanced substrates for surface-enhanced Raman scattering (SERS) with potential for unambiguous single-molecule detection on the atomically well-defined layer of graphene.
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Affiliation(s)
- Xiaolong Zhu
- Department of Photonics Engineering, Technical University of Denmark , DK-2800 Kongens Lyngby, Denmark
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12
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Sigle DO, Perkins E, Baumberg JJ, Mahajan S. Reproducible Deep-UV SERRS on Aluminum Nanovoids. J Phys Chem Lett 2013; 4:1449-52. [PMID: 26282297 DOI: 10.1021/jz4004813] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Surface-enhanced Raman scattering (SERS) with deep-UV excitation is of particular interest because a large variety of biomolecules such as amino acids exhibit electronic transitions in the UV spectral range and resonant excitation dramatically increases the cross section of the associated vibrational modes. Despite its potential, UV-SERS is still little-explored. We present a novel straightforward scalable route to fabricate aluminum nanovoids for reproducible SERS in the deep-UV without the need of expensive lithographic techniques. We adopt a modified template stripping method utilizing a soluble template and self-assembled polymer spheres to create nanopatterned aluminum films. We observe high surface enhancement of approximately 6 orders of magnitude, with excitation in the deep-UV (244 nm) on structures optimized for this wavelength. This work thus enables sensitive detection of organics and biomolecules, normally nonresonant at visible wavelengths, with deep-UV surface-enhanced resonant Raman scattering on reproducible and scalable substrates.
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Affiliation(s)
- Daniel O Sigle
- †Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | | | - Jeremy J Baumberg
- †Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Sumeet Mahajan
- †Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
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Steuwe C, Kaminski CF, Baumberg JJ, Mahajan S. Surface enhanced coherent anti-stokes Raman scattering on nanostructured gold surfaces. NANO LETTERS 2011; 11:5339-43. [PMID: 22074256 DOI: 10.1021/nl202875w] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Coherent anti-Stokes Raman spectroscopy (CARS) is a well-known tool in multiphoton imaging and nonlinear spectroscopy. In this work we combine CARS with plasmonic surface enhancement on reproducible nanostructured surfaces. We demonstrate strong correlation between plasmon resonances and surface-enhanced CARS (SECARS) intensities on our nanostructured surfaces and show that an enhancement of ∼10(5) can be obtained over standard CARS. Furthermore, we find SECARS to be >10(3) times more sensitive than surface-enhanced Raman Spectroscopy (SERS). We also demonstrate SECARS imaging of molecular monolayers. Our work paves the way for reliable single molecule Raman spectroscopy and fast molecular imaging on plasmonic surfaces.
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Affiliation(s)
- Christian Steuwe
- Cavendish Laboratory, Department of Chemical Engineering and Biotechnology, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom
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Huang FM, Wilding D, Speed JD, Russell AE, Bartlett PN, Baumberg JJ. Dressing plasmons in particle-in-cavity architectures. NANO LETTERS 2011; 11:1221-1226. [PMID: 21284375 DOI: 10.1021/nl104214c] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Placing metallic nanoparticles inside cavities, rather than in dimers, greatly improves their plasmonic response. Such particle-in-cavity (PIC) hybrid architectures are shown to produce extremely strong field enhancement at the particle-cavity junctions, arising from the cascaded focusing of large optical cross sections into small gaps. These simply constructed PIC structures produce the strongest field enhancement for coupled nanoparticles, up to 90% stronger than for a dimer. The coupling is found to follow a universal power law with particle-surface separation, both for field enhancements and resonant wavelength shifts. Significantly enhanced Raman signals are experimentally observed for molecules adsorbed in such PIC structures, in quantitive agreement with theoretical calculations. PIC architectures may have important implications in many applications, such as reliable single molecule sensing and light harvesting in plasmonic photovoltaic devices.
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Affiliation(s)
- Fu Min Huang
- Nanophotonics Centre, Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK.
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15
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Jose B, Mallon CT, Forster RJ, Keyes TE. Regio-selective decoration of nanocavity metal arrays: contributions from localized and delocalized plasmons to surface enhanced Raman spectroscopy. Phys Chem Chem Phys 2011; 13:14705-14. [DOI: 10.1039/c1cp20979e] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Ayub M, Ivanov A, Hong J, Kuhn P, Instuli E, Edel JB, Albrecht T. Precise electrochemical fabrication of sub-20 nm solid-state nanopores for single-molecule biosensing. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:454128. [PMID: 21339614 DOI: 10.1088/0953-8984/22/45/454128] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
It has recently been shown that solid-state nanometer-scale pores ('nanopores') can be used as highly sensitive single-molecule sensors. For example, electrophoretic translocation of DNA, RNA and proteins through such nanopores has enabled both detection and structural analysis of these complex biomolecules. Control over the nanopore size is critical as the pore must be comparable in size to the analyte molecule in question. The most widely used fabrication methods are based on focused electron or ion beams and thus require (scanning) transmission electron microscopy and focused ion beam (FIB) instrumentation. Even though very small pores have been made using these approaches, several issues remain. These include the requirement of being restricted to rather thin, mechanically less stable membranes, particularly for pore diameters in the single-digit nanometer range, lack of control of the surface properties at and inside the nanopore, and finally, the fabrication cost. In the proof-of-concept study, we report on a novel and simple route for fabricating metal nanopores with apparent diameters below 20 nm using electrodeposition and real-time ionic current feedback in solution. This fabrication approach inserts considerable flexibility into the kinds of platforms that can be used and the nanopore membrane material. Starting from much larger pores, which are straightforward to make using FIB or other semiconductor fabrication methods, we electrodeposit Pt at the nanopore interface while monitoring its ionic conductance at the same time in a bi-potentiostatic setup. Due to the deposition of Pt, the nanopore decreases in size, resulting in a decrease of the pore conductance. Once a desired pore conductance has been reached, the electrodeposition process is stopped by switching the potential of the membrane electrode and the fabrication process is complete. Furthermore, we demonstrate that these pores can be used for single-biomolecule analysis, such as that of λ-DNA, which we use in a proof-of-concept study. Importantly, our approach is applicable to single nanopores as well as nanopore arrays, and can easily be extended to deposits of metal other than Pt.
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Affiliation(s)
- Mariam Ayub
- Department of Chemistry, Imperial College London, Exhibition Road, London SW7 2AZ, UK
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