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Naor H, Avnir D. Electroless Functionalization of Silver Films by Its Molecular Doping. ACS APPLIED MATERIALS & INTERFACES 2015; 7:26461-26469. [PMID: 26571199 DOI: 10.1021/acsami.5b10619] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present a methodology which by far extends the potential applications of thin conductive silver films achieved by an electroless molecular doping process of the metal with any of the endless functional molecules that the large library of organic molecules offer. The resulting metallic films within which the molecule is entrapped--molecule@Ag--carry both the classical chemical and physical properties of silver films, as well as the function of the entrapped molecule. Raman measurements of the organic molecules from within the silver films provide the first spectroscopic observations from within silver, and clearly show that entrapment, a three-dimensional process, and adsorption, a two-dimensional process, on silver films are distinctly different processes. Three organic molecules, the cationic Neutral red, the anionic Congo red, and the antibacterial agent chlorhexidine digluconate (CH), were used to demonstrate the generality of this method for various types of molecules. We studied the sensitivity of the film conductivity to the type of the molecule entrapped within the film, to its concentration, and to temperature. Dual functionality was demonstrated with CH@Ag films, which are both conductive and have prolonged and high antibacterial activity, a combination of properties that has been unknown so far.
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Affiliation(s)
- Hadas Naor
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem , Jerusalem 91904, Israel
| | - David Avnir
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem , Jerusalem 91904, Israel
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Hammond JL, Bhalla N, Rafiee SD, Estrela P. Localized surface plasmon resonance as a biosensing platform for developing countries. BIOSENSORS-BASEL 2014; 4:172-88. [PMID: 25587417 PMCID: PMC4264378 DOI: 10.3390/bios4020172] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 06/09/2014] [Accepted: 06/17/2014] [Indexed: 11/16/2022]
Abstract
The discovery of the phenomena known as localized surface plasmon resonance (LSPR) has provided the basis for many research areas, ranging from materials science to biosensing. LSPR has since been viewed as a transduction platform that could yield affordable, portable devices for a multitude of applications. This review aims to outline the potential applications within developing countries and the challenges that are likely to be faced before the technology can be effectively employed.
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Affiliation(s)
- Jules L Hammond
- Department of Electronic and Electrical Engineering, University of Bath, Bath BA2 7AY, UK; E-Mails: (J.L.H.); (N.B.); (S.D.R.)
| | - Nikhil Bhalla
- Department of Electronic and Electrical Engineering, University of Bath, Bath BA2 7AY, UK; E-Mails: (J.L.H.); (N.B.); (S.D.R.)
| | - Sarah D Rafiee
- Department of Electronic and Electrical Engineering, University of Bath, Bath BA2 7AY, UK; E-Mails: (J.L.H.); (N.B.); (S.D.R.)
| | - Pedro Estrela
- Department of Electronic and Electrical Engineering, University of Bath, Bath BA2 7AY, UK; E-Mails: (J.L.H.); (N.B.); (S.D.R.)
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Jang GG, Blake P, Roper DK. Rate-limited electroless gold thin film growth: a real-time study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:5476-5486. [PMID: 23560793 DOI: 10.1021/la304154u] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Time-resolved, in situ spectroscopy of electroless (EL) gold (Au) films combined with electron microscopy showed that the deposition rate increased up to two-fold on surfaces swept by the bulk flow of adjacent fluid at Reynolds numbers less than 1.0, compared to batch immersion. Deposition rates from 5.0 to 9.0 nm/min and thicknesses of the EL Au film from 20 to 100 nm, respectively, increased predictably with flow rate at conditions when the deposition was limited primarily by Fickian diffusion. Time-frames were identified for metal island nucleation, growth, and subsequent film development during EL Au deposition by real-time UV-visible spectroscopy of photoluminescence (PL) and surface plasmon features of nanoscale metal deposits. Film thicknesses measured by scanning electron microscopy and X-ray photoelectron spectroscopy paired with real-time optical spectroscopy of kinetic aspects of plasmon and PL optical features indicated that Au film deposition on surfaces swept by a steady flow of adjacent fluid can be primarily diffusion limited.
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Affiliation(s)
- Gyoung Gug Jang
- Ralph E. Martin Department of Chemical Engineering, University of Arkansas, Arkansas 72701, United States
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Bantz KC, Meyer AF, Wittenberg NJ, Im H, Kurtuluş Ö, Lee SH, Lindquist NC, Oh SH, Haynes CL. Recent progress in SERS biosensing. Phys Chem Chem Phys 2011; 13:11551-67. [PMID: 21509385 PMCID: PMC3156086 DOI: 10.1039/c0cp01841d] [Citation(s) in RCA: 331] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This perspective gives an overview of recent developments in surface-enhanced Raman scattering (SERS) for biosensing. We focus this review on SERS papers published in the last 10 years and to specific applications of detecting biological analytes. Both intrinsic and extrinsic SERS biosensing schemes have been employed to detect and identify small molecules, nucleic acids, lipids, peptides, and proteins, as well as for in vivo and cellular sensing. Current SERS substrate technologies along with a series of advancements in surface chemistry, sample preparation, intrinsic/extrinsic signal transduction schemes, and tip-enhanced Raman spectroscopy are discussed. The progress covered herein shows great promise for widespread adoption of SERS biosensing.
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Affiliation(s)
- Kyle C. Bantz
- Department of Chemistry, University of Minnesota, Twin Cities
| | - Audrey F. Meyer
- Department of Chemistry, University of Minnesota, Twin Cities
| | - Nathan J. Wittenberg
- Department of Electrical and Computer Engineering, University of Minnesota, Twin Cities
| | - Hyungsoon Im
- Department of Electrical and Computer Engineering, University of Minnesota, Twin Cities
| | - Özge Kurtuluş
- Department of Chemistry, University of Minnesota, Twin Cities
| | - Si Hoon Lee
- Department of Biomedical Engineering, University of Minnesota, Twin Cities
| | - Nathan C. Lindquist
- Department of Electrical and Computer Engineering, University of Minnesota, Twin Cities
| | - Sang-Hyun Oh
- Department of Electrical and Computer Engineering, University of Minnesota, Twin Cities
- Department of Biomedical Engineering, University of Minnesota, Twin Cities
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Gong J, Lipomi DJ, Deng J, Nie Z, Chen X, Randall NX, Nair R, Whitesides GM. Micro- and nanopatterning of inorganic and polymeric substrates by indentation lithography. NANO LETTERS 2010; 10:2702-8. [PMID: 20557080 DOI: 10.1021/nl101675s] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This paper describes the use of a nanoindenter, equipped with a diamond tip, to form patterns of indentations on planar substrates (epoxy, silicon, and SiO(2)). The process is called "Indentation Lithography" (IndL). The indentations have the form of pits and furrows, whose cross-sectional profiles are determined by the shapes of the diamond indenters, and whose dimensions are determined by the applied load and hardness of the substrate. IndL makes it possible to indent hard materials, to produce patterns with multiple levels of relief by changing the loading force, and to control the profiles of the indentations by using indenters with different shapes. This paper also demonstrates the transfer of indented patterns to elastomeric PDMS stamps for soft lithography, and to thin films of evaporated gold or silver. Stripping an evaporated film from an indented template produces patterns of gold or silver pyramids, whose tips concentrate electric fields. Patterns produced by IndL can thus be used as substrates for surface-enhanced Raman scattering (SERS) and for other plasmonic applications.
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Affiliation(s)
- Jinlong Gong
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
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Lee SH, Bantz KC, Lindquist NC, Oh SH, Haynes CL. Self-assembled plasmonic nanohole arrays. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:13685-93. [PMID: 19831350 DOI: 10.1021/la9020614] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We present a simple and massively parallel nanofabrication technique to produce self-assembled periodic nanohole arrays over a millimeter-sized area of metallic film, with a tunable hole shape, diameter, and periodicity. Using this method, 30 x 30 microm(2) defect-free areas of 300 nm diameter or smaller holes were obtained in silver; this area threshold is critical because it is larger than the visible wavelength propagation length of surface plasmon waves ( approximately 27 microm) in the silver film. Measured optical transmission spectra show highly homogeneous characteristics across the millimeter-size patterned area, and they are in good agreement with FDTD simulations. The simulations also reveal intense electric fields concentrated near the air/silver interface, which was used for surface-enhanced Raman spectroscopy (SERS). Enhancement factors (EFs) measured with different hole shape and excitation wavelengths on the self-assembled nanohole arrays were 10(4)-10(6). With an additional Ag electroless plating step, the EF was further increased up to 3 x 10(6). The periodic nanohole arrays produced using this tunable self-assembly method show great promise as inexpensive SERS substrates as well as surface plasmon resonance biosensing platforms.
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Affiliation(s)
- Si Hoon Lee
- Department of Biomedical Engineering, 312 Church Street SE, University of Minnesota, Twin Cities, Minneapolis, Minnesota 55455, USA
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Nagpal P, Lindquist NC, Oh SH, Norris DJ. Ultrasmooth Patterned Metals for Plasmonics and Metamaterials. Science 2009; 325:594-7. [PMID: 19644116 DOI: 10.1126/science.1174655] [Citation(s) in RCA: 393] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Surface plasmons are electromagnetic waves that can exist at metal interfaces because of coupling between light and free electrons. Restricted to travel along the interface, these waves can be channeled, concentrated, or otherwise manipulated by surface patterning. However, because surface roughness and other inhomogeneities have so far limited surface-plasmon propagation in real plasmonic devices, simple high-throughput methods are needed to fabricate high-quality patterned metals. We combined template stripping with precisely patterned silicon substrates to obtain ultrasmooth pure metal films with grooves, bumps, pyramids, ridges, and holes. Measured surface-plasmon–propagation lengths on the resulting surfaces approach theoretical values for perfectly flat films. With the use of our method, we demonstrated structures that exhibit Raman scattering enhancements above 107 for sensing applications and multilayer films for optical metamaterials.
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Affiliation(s)
- Prashant Nagpal
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA
| | - Nathan C. Lindquist
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - Sang-Hyun Oh
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - David J. Norris
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA
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Jones CL, Bantz KC, Haynes CL. Partition layer-modified substrates for reversible surface-enhanced Raman scattering detection of polycyclic aromatic hydrocarbons. Anal Bioanal Chem 2009; 394:303-11. [DOI: 10.1007/s00216-009-2701-4] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2008] [Revised: 02/05/2009] [Accepted: 02/09/2009] [Indexed: 11/28/2022]
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