Surface-enhanced Raman scattering immunoassays using a rotated capture substrate

TitleSurface-enhanced Raman scattering immunoassays using a rotated capture substrate
Publication TypeJournal Article
Year of Publication2007
AuthorsDriskell JD, Uhlenkamp JM, Lipert RJ, Porter MD
Journal TitleAnalytical Chemistry
Volume79
Pages4141-4148
Date PublishedJun
Type of ArticleArticle
ISBN Number0003-2700
Accession NumberISI:000246842100020
KeywordsANTIBODY, ANTIGEN, ATOMIC-FORCE MICROSCOPY, DISK ELECTRODE, FLOW SYSTEM, immunogold labels, MASS-TRANSFER, nanoparticles, plasmon resonance, SELF-ASSEMBLED MONOLAYERS
Abstract

A rapid, sensitive format for immunosorbent assays has been developed to meet the increasing levels of performance (i.e., reduction of incubation times and detection limits) demanded in the medical, veterinary, and bioterrorism prevention arenas. This paper introduces the concept of a rotating capture substrate as a facile means to increase the flux of antigen and label to the solid-phase surface and thereby reduce assay time. To this end, a sandwich-type assay is carried out that couples the specificity of antibody-antigen interactions with the high sensitivity of surface-enhanced Raman scattering detection. To investigate this strategy, polyclonal anti-rabbit IgG was immobilized on a gold capture substrate via a thiolate coupling agent. The capture substrate, capable of controlled rotation, was then immersed in a sample solution containing rabbit IgG, which served as a model analyte. After binding the target IgG, the substrates were immersed and rotated in an extrinsic Raman label (ERL) labeling solution, which is composed of gold nanoparticles (60 nm) coated with an aromatic moiety as the Raman scatterer and an antibody as the biospecific recognition element. The effect of substrate rotation on both the antigen binding and ERL labeling steps was investigated. Implementation of optimized rotation conditions resulted in the reduction of assay times from 24 h to 25 min and a 10-fold improvement in the limit of detection. Finally, the developed protocol was applied to the detection of rabbit IgG suspended in goat serum, which served to assess performance in a biological matrix.

DOI10.1021/ac0701031
Alternate JournalAnal. Chem.