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


Nanosphere lithography coupled to 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 array of nanoprisms, chosen as a benchmark, significantly higher performances both in local and in bulk sensitivity have been found, in agreement with electrodynamic simulations based on finite-element methods.

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Publication details

The article was received on 20 Mar 2017, accepted on 13 Jun 2017 and first published on 14 Jun 2017

Article type: Paper
DOI: 10.1039/C7NR01982C
Citation: Nanoscale, 2017, Accepted Manuscript
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    Gold-silver alloy semi-nanoshell arrays for label-free plasmonic biosensors

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

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