Molecular film technology for biosensors

Two different molecular film technologies have been developed for fabricating biosensors. Firstly, bovine serum albumin spread on the air-water interface was cross-linked and transferred onto the glass surface, on which various molecular assemblies were formed by the bioaffinity technique. Secondly, a protein monolayer was adsorbed from an aqueous phase on the potential-controlled electrode surface, which was followed by electrochemical polymerization and deposition of pyrrole between the protein molecules to make the adsorbed protein film conductive. A unique optical biosensor for taste has been fabricated by depositing fluorophore-containing Langmuir-Blodgett (LB) films on the glass surface. Each layer of the LB films exhibits its characteristic fluorescence peak which is quenched or enhanced in contact with taste substances. The sensor consisted of three different LB films containing pyrene and anthracene and deposited on a glass plate. Novel performance was demonstrated with the response of the sensor to glutamate and nucleotide umami substances.