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Indexed by:期刊论文

Date of Publication:2012-10-21

Journal:ANALYST

Included Journals:PubMed、SCIE、Scopus

Volume:137

Issue:20

Page Number:4712-4719

ISSN No.:0003-2654

Abstract:Gold nanoparticle labelling has been shown to produce a remarkable improvement in sensitivity for small molecule detection based on Surface Plasmon Resonance (SPR) bio-sensing. The LSPR (localised SPR)-SPR coupling effect and size/mass-material properties associated with gold nanoparticles are the two main factors to change the SPR resonance condition and cause the enhancement. In this paper we examine the separation of these factors in the context of a classical SPR bio-interaction assay format, and consider the implications on the design of biodetection systems to maximise response. The coupling effect plays a distance dependent role, which allows it to be mapped. The dominant enhancement associated with this factor only occurs within similar to 8 nm for a 20 nm gold nanoparticle and is changing by similar to 7 nm wavelength shift/nm distance from the Au SPR thin film. Beyond this distance, the size/mass associated with the nanoparticle itself dominates the enhancement. This is demonstrated in a 20-mer DNA sequence sandwich detection, where the enhancement ratio between the coupling effect and the mass is similar to 1.5 : 1. This simple method for deconvolution of the mass and coupling effects allows consideration of formats with LSPR nanoparticle labelling for small molecule detection and the best design of the labelling geometry.