Development of an electrochemiluminescent(ECL) immunosensor; Determination of antibody concentration and electrochemiluminescence mechanism

We designed a technique of continuous and simple immunoassay using an electrochemiluminescence flow cell for monitoring antibody or antigen concentration as an indication of optimal amount of immunosupressors, and attempted to clarify enhanced ECL intensity produced by the binding of antigen and antibody. Luminol-labeled antigens were used to measure the concentration of these antibodies. Luminol-labeled anti-human serum albumin(HSA) antibody was used to measure HSA concentration. Both anti-HSA antibody and anti-immunoglobulin G antibody ranging from 0 to 22 mg/ml, 0 to 200 μg/ml, respectively, increased the ECL intensity of aqueous luminol- labeled antigens HSA ranging from 0 to 38 μM also increased the ECL of luminol-labeled anti-HSA antibody. The ECL intensity of luminol-labeled antigen also increased with antibody concentration in bovine plasma. These results demonstrate that this system is promising for the homogeneous immunoassay of antibodies or antigens and the principal reason of ECL intensity enhancement is an increase in quantum yield of luminol caused by the binding of antigen and antibody.