Improved enzyme retention from an electropolymerized polypyrrole-alginate matrix in the development of biosensors

A novel pyrrole-alginate was synthesized providing a gel by Ca2+ cross-linking. The subsequent in situ electrochemical polymerization of the linked pyrrole groups at 0.93 V led to the formation of a composite polypyrrole-gel matrix exhibiting a greater enzyme retention as well as increased alginate stability towards the destructive effect of phosphate anions unlike the natural alginate gel. The presence of the electropolymerized chains was clearly indicated by the decrease of the permeability when compared to natural alginate gel, namely 2.7 x 10(-2) and 3.65 x 10(-1) cm s(-1) respectively, using as an electroactive permeate, hydroquinone. Moreover, the analytical performance of glucose oxidase-based composite alginate for the determination of glucose was determined. (c) 2005 Elsevier B.V. All rights reserved.