A new type of enzyme immunosensor using antigen-bound membrane and multivalent antibody (Fab'-alpha-amylase conjugate)

An enzyme immunosensor using an antigen-bound membrane and Fab'- alpha -amylase conjugates has been developed to improve the reproducibility and capability for multi-cycle operations. It was shown that the new enzyme immunosensor has a cyclic lifetime twice as long as that of the sensor using an antibody-bound membrane, and that serum theophylline could be detected at levels as low as 5 mu g/ml. The proposed system may be useful for repeated use of the enzyme immunosensor without replacing the membrane.