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Surface-enhanced Raman spectroscopy-active substrates: adapting the shape of plasmonic nanoparticles for different biological applications
Journal article

Surface-enhanced Raman spectroscopy-active substrates: adapting the shape of plasmonic nanoparticles for different biological applications

Elina A Vitol, Gary Friedman and Yury Gogotsi
Journal of nanoscience and nanotechnology, v 14(4), pp 3046-3051
Apr 2014
PMID: 24734732

Abstract

Gold - chemistry Glycine - chemistry Nanoparticles - chemistry Anisotropy Nanoparticles - ultrastructure Spectrum Analysis, Raman - methods Cell Wall - chemistry Escherichia coli - chemistry Spectrophotometry, Ultraviolet Staphylococcus aureus - chemistry
We discuss the relationship between the shape of plasmonic nanoparticles and the biological surface-enhanced Raman spectroscopy (SERS) applications which they can enable. As a step forward in developing SERS-active substrates adapted to a particular application, we demonstrate that a modification of the widely used protocol for the sodium citrate mediated reduction of chloroauric acid, which is typically employed only for obtaining spherical gold nanoparticles, can yield flat polygonal nanoparticles at room temperature and a decreased amount of the reducing agent. The significant advantage of the described approach is that it allows for synthesis of nanoparticles with different geometries using a well-established synthesis protocol without the need for any additional chemicals or special synthesis apparatus. By contrasting spherical and anisotropically shaped nanoparticles, we demonstrate that multifaceted nanoparticles with sharp edges are better suitable for SERS analysis of low concentration analytes requiring strong SERS enhancement. On the other hand, gold nanoparticles with isotropic shapes, while giving a smaller enhancement, can provide a more reproducible SERS signal. This is important for analytical applications of complex biological systems where large SERS enhancement may not always be required, whereas data reproducibility and minimal false positive rate are imperative. Using a SERS-active substrate comprising isotropically shaped gold nanoparticles, we demonstrate the differences between Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria, attributable to the outer membrane and peptidoglycan layer, with the level of detail which has not been previously reported with optical spectroscopic techniques.

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Collaboration types
Domestic collaboration
Web of Science research areas
Chemistry, Multidisciplinary
Materials Science, Multidisciplinary
Nanoscience & Nanotechnology
Physics, Applied
Physics, Condensed Matter
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