A novel ferrocene encapsulated palladium-linked ormosil-based electrocatalytic dopamine biosensor

A novel finding on the development of electrocatalytic biosensor for dopamine is reported. The new electrocatalytic dopamine biosensor is developed using ferrocene encapsulated palladium (Pd)-linked organically-modified sol-gel glass (ormosil). The alkoxy precursors used for the preparation of new ormosil-based electrocatalytic biosensor are palladium-linked glycidoxypropyltrimethoxysilane and trimethoxysilane. The optimum concentrations of these precursors are added in aqueous solution of ferrocene monocarboxylic acid and HCl followed by gelation for 30 h at 25 degreesC to form ormosil. The ferrocene encapsulated ormosil is characterized based on cyclic voltammetric measurements. The CV results shows peak separation of 57-59 mV and a linear relation between peak current and square root of scan rate suggesting well behaved reversible electrochemistry of ormosil encapsulated ferrocene. The CV results and the detection of ferrocene in working medium shows that ferrocene is not leached out of ormosil matrix. The tyrosinase is immobilized within polyvinyl alcohol over the ferrocene encapsulated new ormosil and finally mounted using nucleopore membrane. The electrocatalytic response of immobilized tyrosinase over new ormosil is observed and the results are reported. The performance, stability, and reproducibility of new ormosil-based dopamine biosensor are reported. (C) 2001 Elsevier Science B.V. All rights reserved.