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Journal of Biomedical Optics • Open Access

Ultrasensitive protein detection in blood serum using gold nanoparticle probes by single molecule spectroscopy
Author(s): Jiji Chen; Chungang Wang; Joseph M. Irudayaraj

Paper Abstract

A one-step rapid and ultrasensitive immunoassay capable of detecting proteins in blood serum is developed using gold nanoprobes and fluorescence correlation spectroscopy (FCS). In this approach we take advantage of the inherent photoluminescence property of gold nanoparticles (GNPs) to develop a fluorophore-free assay to observe binding entities by monitoring the diffusion of bound versus unbound molecules in a limited confocal volume. 40-nm GNPs conjugated separately with rabbit anti-IgG (Fc) and goat anti-IgG (Fab) when incubated in blood serum containing IgG forms a sandwich structure constituting dimers and oligomers that can be differentiated by to detect IgG in blood serum at a limit of detection (LOD) of 5 pg/ml. The novelty of integrating GNPs with FCS to develop a sensitive blood immunoassay brings single molecule methods one step closer to the clinic.

Paper Details

Date Published: 1 July 2009
PDF: 3 pages
J. Biomed. Opt. 14(4) 040501 doi: 10.1117/1.3183789
Published in: Journal of Biomedical Optics Volume 14, Issue 4
Show Author Affiliations
Jiji Chen, Purdue Univ. (United States)
Chungang Wang, Purdue Univ. (United States)
Joseph M. Irudayaraj, Purdue Univ. (United States)

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