Multianalyte immunoassay based on surface-enhanced Raman spectroscopy

In this paper, two immunoassay methods based on SERS are developed for multiplex analysis, both of which stemmed from the concept of forming a sandwich structure 'capture antibody substrate/antigen/Raman-reporter-labeled immuno-nanoparticles'. They are two-molecule labeled one-nanoparticle and one-molecule labeled two-nanoparticle methods. In both the methods, two different antibodies covalently bound to a solid substrate can specifically capture two different antigens from a sample. The captured antigens in turn bind selectively to their corresponding antibodies immobilized on Raman-reporter-labeled nanoparticles. Multianalyte immunoassay is successfully demonstrated by the detection of characteristic Raman bands of the probe molecules only when the antigen and antibody are matched. Copyright (C) 2007 John Wiley & Sons, Ltd.