Integration of an immunosorbent assay system: Analysis of secretory human immunoglobulin A on polystyrene beads in a microchip

An immunosorbent assay system was integrated into a glass microchip. Polyst yrene beads were introduced into a microchannel, and then human secretory i mmunoglobulin A (s-IgA) adsorbed on the bead surface was reacted with collo idal gold conjugated anti-s-IgA antibody and detected by a thermal lens mic roscope. The scale merits of liquid microspace on the molecular behavior re markably contributed to reduced assay time. The integration cut the time ne cessary for the antigen-antibody reaction by 1/90, thus shortening the over all analysis time from 24 h to less than 1 h. Moreover, troublesome operati ons required for conventional immunosorbent assays could be replaced by sim ple operations.