The modification of the surface of the fiber optic probe by bio-recognizing molecules is essential for detecting interest target by evanescent wave fiber optic immunosensor. In this study, microcystin-LR (MC-LR) was chosen as the example substance. Hapten-carrier conjugates MC-LR-Ovalbumin were synthesized by mixing MC-LR and ovalbumin (OVA) activated by glutaraldehyde, and then the conjugates were immobilized onto the silane layer on the probe with a heterobifunctional crosslinker. The probe modified was evaluated by XPS and an evanescent wave all-fiber immunosensor. The results showed that surface chemical compositions of the probe obviously changed at different modification steps, MC-LR-OVA was covalently bound with the probe surface, strong binding of antibody of MC-LR and low non-specific adsorption to other antibody was monitored, and good performance of regeneration was achieved. As a result, this modification method can be used for preparation of probe for the detection of low molecule pollutants.

Key words: fiber-optic immunosensor, surface modification, probe, evanescent wave, microcystin-LR