The Detection of Antigen-Antibody Recognition on an Array Chip by Surface Plasmon Field-Enhanced Fluorescence Imaging (SPFI)

Abstract

Multi-array analysis method recently attracts attention as a useful technique to detect antigen-antibody interactions in a small amount of reagents. Surface plasmon resonance (SPR) has been used as one of the highly sensitive techniques which can detect antigen-antibody interaction in the multi-array coated by a thin metal film. We proposed the surface plasmon field-enhanced fluorescence Imaging (SPFI) with higher sensitivity than SPR detection. The fluorescence from fluorescence molecules near the substrate (within 40 nm) is quenched by a thin metal film as found from previous studies. Therefore the change of distance due to the interaction of the protein (antigen) in cell with antibody immobilized at the substrate surface was monitored by the change of the fluorescence intensity using SPFI. Further we fabricated array spots on the substrate using a self assembled monolayer (SAM) possible to suppress the non-specific adsorption out of the spot exposed to UV light, and the antibody was prepared into the spots. Two kinds of antibodies modified with fluorescent-dyes were immobilized to the different array spots. Our SPFS system can recognize binding of cells based on the specific antigen-antibody interaction in the multi-array system.

Sensitive detection of interleukin-6 on a plasmonic chip by grating-coupled surface-plasmon-field-enhanced fluorescence imaging

“…Our group has applied SPF imaging (SPFI) to sensitive biodetection. 7,8) Chip surfaces were patterned with a Langmuir-Blodgett film 8) and a self-assembled monolayer, 9) and multiple spots can be detected simultaneously by SPFI.…”