Laccase containing sol-gel based optical biosensors

Laccase-containing sol-gels were synthesized by hydrolysis and condensation polymerization of tetramethyl orthosilicates. Two types of laccase containing sol-gel based optical biosensors were designed and tested. The first type is based on 2-8 mm thick monolith sol-gel blocks. It was observed that laccase-containing sol-gel blocks accumulate high molecular weight products of oxidation of the laccase substrate-2,6-dimethoxyphenol. This leads to at least ten fold increase of optical bioassay sensitivity in comparison with the homogeneous phase. The response time of such biosensors is 3-24 hours. The second type of biosensor is based on laccase-containing 0.3 mm diameter sol-gel particles in a flow cell and includes an optical fiber measuring system. This sensor is characterized by a fast response time in comparison with the first type. The latter biosensor also possesses a homogeneous phase assay sensitivity and yields a linear calibration curve.