ELECTROPOLYMERIZED M-PHENYLENEDIAMINE AS A MEANS TO IMMOBILIZE ACTIVEPROTEIN ON THICKNSS-SHEAR-MODE QUARTZ-CRYSTAL

Electropolymerized m-phenylenediamine was used as an active coating fo r immobilizing urease and lectin on a gold-plated thickness-shear-mode (TSM) crystal. To enhance effectiveness of immobilization, a bilayer polymer film composed of polyaniline and poly-m-phenylenediamine was p roposed. Compared with single poly-m-phenylenediamine film, the bilaye r polymer film gave better results in terms of immobilizing capacity, stability and reproductivity. On this bilayer-film-coated TSM quartz c rystal, the amount of immobilized lectin was estimated about 1.8 mu g/ cm(2). Detection of purified human erythrocytes is demonstrated as an example of potential application of this lectin-modified TSM biosensor in clinic.