Fiber-optic sensor with a sandwich binding technique for fluoroimmunoassay

We report the development of a fiber-optic sensor based on the principle of the sandwich binding technique for the fluoro-immunoassay. Anti-mouse immunoglobulin G (IgG) antibody was immobilized on the membrane mounted to the edge of the fiber. The sensor was exposed to the solution containing mouse IgG and then allophycocyanin conjugated anti-mouse IgG antibody was added. The helium-neon (He-Ne) laser provides excitation of the sandwich binding antigen-antibody complex. This results in fluorescence emission at the membrane. Increase in the fluorescence intensity from sensing tip was proportional to the amount of mouse IgG in the sample. A linear relationship was obtained betweenthe fluorescence intensity increase and the mouse IgG concentration in the range 0.3 - 9.0 pg/ml.