Surface-enhanced Raman scattering measurement from a lipid bilayer encapsulating a single decahedral nanoparticle mediated by an optical trap

Wright, Amanda J.; Richens, Joanna L.; Bramble, J.P.; Cathcart, N.; Kitaev, V.; O'Shea, Paul; Hudson, A.J.

Abstract

We present a new technique for the study of model membranes on the length-scale of a single nanosized liposome. Silver decahedral nanoparticles have been encapsulated by a model unilamellar lipid bilayer creating nano-sized lipid vesicles. The metal core has two roles (i) increasing the polarizability of vesicles, enabling a single vesicle to be isolated and confined in an optical trap, and (ii) enhancing Raman scattering from the bilayer, via the high surface-plasmon field at the sharp vertices of the decahedral particles. Combined this has allowed us to measure a Raman fingerprint from a single vesicle of 50 nmdiameter, containing just ∼104 lipid molecules in a bilayer membrane over a surface area of <0.01 µm2, equivalent to a volume of approximately 1 zepto-litre. Raman scattering is a weak and inefficient process and previous studies have required either a substantially larger bilayer area in order to obtain a detectable signal, or the tagging of lipid molecules with a chromophore to provide an indirect probe of the bilayer. Our approach is fully label-free and bio-compatible and, in the future, it will enable much more localized studies of the heterogeneous structure of lipid bilayers and of membrane-bound components than is currently possible.

Citation

Wright, A. J., Richens, J. L., Bramble, J., Cathcart, N., Kitaev, V., O'Shea, P., & Hudson, A. (in press). Surface-enhanced Raman scattering measurement from a lipid bilayer encapsulating a single decahedral nanoparticle mediated by an optical trap. Nanoscale, 8(36), https://doi.org/10.1039/C6NR05616D

• Journal Article Type: Article
• Acceptance Date: Aug 30, 2016
• Online Publication Date: Sep 2, 2016
• Deposit Date: Oct 4, 2016
• Publicly Available Date: Oct 4, 2016
• Journal: Nanoscale
• Print ISSN: 2040-3364
• Electronic ISSN: 2040-3372
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 8
• Issue: 36
• DOI: https://doi.org/10.1039/C6NR05616D
• Public URL: https://nottingham-repository.worktribe.com/output/819654
• Publisher URL: http://pubs.rsc.org/en/Content/ArticleLanding/2016/NR/C6NR05616D#!divAbstract
• Contract Date: Oct 4, 2016