Kaminska, Agnieszka, Obianuju, Inya-Agha, Forster, Robert J. and Keyes, Tia E. (2008) Chemically bound gold nanoparticle arrays on silicon: assembly, properties and SERS study of protein interactions. Physical Chemistry Chemical Physics, 10 (28). pp. 4172-4180. ISSN 1463-9084
Abstract
A highly reproducible and facile method for formation of ordered 2 dimensional arrays of CTAB protected 50 nm gold nanoparticles bonded to silicon wafers is described. The silicon wafers have been chemically modified with long-chain silanes terminated with thiol that penetrate the CTAB bilayer and chemically bind to the underlying gold nanoparticle. The silicon wafer provides a reproducibly smooth, chemically functionalizable and non-fluorescent substrate with a silicon phonon mode which may provide a convenient internal frequency and intensity calibration for vibrational spectroscopy. The CTAB bilayer provides a potentially biomimetic environment for analyte, yet allows a sufficiently small nanoparticle separation to achieve a significant electric field enhancement. The arrays have been characterized using SEM and Raman spectroscopy. These studies reveal that the reproducibility of the arrays is excellent both between batches (< 10% RSD) and across a single batch (< 5% RSD). The arrays also exhibit good stability, and the effect of temperature on the arrays was also investigated. The interaction of protein and amino acid with the nanoparticle arrays was investigated using Raman microscopy to investigate their potential in bio-SERS spectroscopy. Raman of phenylalanine and the protein bovine pancreatic trypsin inhibitor, BPTI were studied using 785 nm excitation, coincident with the surface plasmon absorbance of the array. The arrays exhibit SERS enhancements of the order of 2.6 x 104 for phenylalanine, the standard deviation on the relative intensity of the 1555 cm-1 mode of phenylalanine is less than 10% for 100 randomly distributed locations across a single substrate and less than 20% between different substrates. Significantly, comparisons of the Raman spectra of the protein and phenlyalanine in solution and immobilized on the nanoparticle arrays indicates that the protein is non-randomly orientated on the arrays. Selective SERS enhancements suggest that aromatic residues penetrate through the bilayer inducing conformational changes in the protein.
Metadata
Item Type: | Article (Published) |
---|---|
Refereed: | Yes |
Subjects: | Physical Sciences > Chemistry |
DCU Faculties and Centres: | DCU Faculties and Schools > Faculty of Science and Health > School of Chemical Sciences Research Institutes and Centres > National Centre for Sensor Research (NCSR) |
Publisher: | Royal Society of Chemistry |
Official URL: | http://dx.doi.org/10.1039/b803007c |
Use License: | This item is licensed under a Creative Commons Attribution-NonCommercial-Share Alike 3.0 License. View License |
Funders: | Science Foundation Ireland |
ID Code: | 4618 |
Deposited On: | 17 Jun 2009 12:29 by Ciaran McKenna . Last Modified 19 Jul 2018 14:44 |
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