Selective Detection of Antigen-Antibody Reaction Using Si Ring Optical Resonators

Abstract

Si ring optical resonators have been fabricated by the Si LSI technology using electron beam lithography and reactive ion etching. The resonator is applied for sensing receptor-analyte reaction using silicon-binding protein, Si-tag, which enables receptors immobilized on a Si dioxide surface with a controlled orientation. For the receptor, the major house-dust mite allergen called Der f 2 was used, and for the analyte anti-Der f 2 immunoglobulin type G (IgG), which is selectively bound to Der f 2, was used. Antiserum against Der f 2, which contains anti-Der f 2 IgG, was diluted to 1/100 with the pure water, and exposed to the resonator on which the Der f 2 was adsorbed with the Si-tag. Then the resonance wavelength was shifted by 0.18 nm, while exposure of the normal rabbit serum containing no Der f 2 IgG resulted in the peak shift less than half (0.07 nm). These results indicate the selective reaction between Der f 2 and anti-Der f 2 IgG.