Polyvinylalcohol-collagen membranes for enzyme immobilization

PVA-collagen membranes were prepared by co-crosslinking a mixture of PVA-collagen with epichlorohydrin, to obtain membranes 35 ?m thick (dried). Best results were recorded with a composition of 6% PVA and 6% collagen. CM and AE derivatives were obtained by treating the PVA-collagen membranes with monochloroacetic acid and chloroethylamine, respectively. The CM-PVA-collagen membranes were used for enzyme immobilization by carbodiimide, while PVA-collagen and AE-PVA-collagen were used for the carbodiimide or glutaraldehyde procedures. The immobilizations were performed under identical conditions using the GOD enzyme. The different immobilized GOD membranes were applied on amperometric oxygen electrodes and the decrease of the oxygen concentration in various glucose samples was measured. Best results - a relatively short response time (2-3 min) with a response rate of 80% of the saturation value per minute (80%/min) for a 0.1 M glucose solution - were obtained in the case of AE-PVA-collagen membranes activated with glutaraldehyde. A linear calibration curve was recorded with different standard solutions by multiple additions and flow injection techniques. The procedure for preparing this new type of membrane is easy to perform and the preliminary results indicate some attractive perspectives for its use in various fields including clinical analysis.