Issue 28, 2017

Gold–silver alloy semi-nanoshell arrays for label-free plasmonic biosensors

Abstract

Nanosphere lithography coupled with reactive ion etching has been used to synthesize hexagonal ordered arrays of Au–Ag bimetallic semi-nanoshells to be used as plasmonic biosensors. The degree of lateral interaction between adjacent semi-nanoshells can be controlled by tailoring the reactive ion etching time in order to boost the global plasmonic properties through the formation of near-field hot-spots, which in turn can improve the sensitivity of the biosensors. To test the efficiency of the proposed system as a biosensor, we used an established protocol for the detection of biomolecules (local sensitivity), based on the receptor–ligand approach and using the biotin–streptavidin model system. We also tested the sensitivity to a homogeneous change in the refractive index of the buffer over the sensor (bulk sensitivity). Comparing the obtained results to those of an array of nanoprisms, chosen as a benchmark, significantly higher performances both in local and bulk sensitivities have been found, in agreement with electrodynamics simulations based on finite-element methods.

Graphical abstract: Gold–silver alloy semi-nanoshell arrays for label-free plasmonic biosensors

Supplementary files

Article information

Article type
Paper
Submitted
20 Mar 2017
Accepted
13 Jun 2017
First published
14 Jun 2017

Nanoscale, 2017,9, 10117-10125

Gold–silver alloy semi-nanoshell arrays for label-free plasmonic biosensors

V. Russo, N. Michieli, T. Cesca, C. Scian, D. Silvestri, M. Morpurgo and G. Mattei, Nanoscale, 2017, 9, 10117 DOI: 10.1039/C7NR01982C

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