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Nanoparticle-enhanced surface plasmon resonance detection of proteins at attomolar concentrations : comparing different nanoparticle shapes and sizes

Kwon, M. J. and Lee, J. and Wark, Alastair and Lee, Hye Jin (2012) Nanoparticle-enhanced surface plasmon resonance detection of proteins at attomolar concentrations : comparing different nanoparticle shapes and sizes. Analytical Chemistry, 84 (3). pp. 1702-1707. ISSN 0003-2700

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Abstract

The application of biofunctionalized nanoparticles possessing various shapes and sizes for the enhanced surface plasmon resonance (SPR) detection of a protein biomarker at attomolar concentrations is described. Three different gold nanoparticle shapes (cubic cages, nanorods and quasi-spherical) with each possessing at least one dimension in the 40-50 nm range were systematically compared. Each nanoparticle (NP) was covalently functionalized with an antibody (anti-thrombin) and used as part of a sandwich assay in conjunction with a Au SPR chip modified with a DNA-aptamer probe specific to thrombin. The concentration of each NP-antibody conjugate solution was first optimized prior to establishing that the quasi-spherical nanoparticles resulted in the greatest enhancement in sensitivity with the detection of thrombin at concentrations as low as 1 aM. When nanorod and nanocage antibody conjugates were instead used, the minimum target concentrations detected were 10 aM (rods) and 1 fM (cages). This is a significant improvement (>103) on previous NP-enhanced SPR studies utilizing smaller (~15 nm) gold NP conjugates and is attributed to the functionalization of both the NP and chip surfaces resulting in low nonspecific adsorption as well as a combination of density increases and plasmonic coupling inducing large shifts in the local refractive index at the chip surface upon nanoparticle adsorption.

Item type: Article
ID code: 37046
Keywords: plasmon resonance detection , proteins, nanoparticle shapes , attomolar concentrations, Chemistry, Analytical Chemistry
Subjects: Science > Chemistry
Department: Faculty of Science > Pure and Applied Chemistry
Technology and Innovation Centre > Bionanotechnology
Related URLs:
    Depositing user: Pure Administrator
    Date Deposited: 25 Jan 2012 11:05
    Last modified: 11 Apr 2014 08:23
    URI: http://strathprints.strath.ac.uk/id/eprint/37046

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