Development of a novel amperometric glucose biosensor based on copolymer of pyrrole-PAMAM dendrimers

Glucose oxidase (GOx) was covalently immobilised onto an electrochemically prepared co-polymer composed of amidoamine-pyrrole dendrimers, for the construction of an amperometric glucose biosensor. First, second, and third generation amidoamine-pyrrole dendrimers with branched amine periphery and focal pyrrole functionality were synthesised via divergent pathways. Dendronised polypyrrole was synthesised by electrochemical copolymerisation of the aminoamine-pyrrole dendrimers from pyrrole monomers. These copolymers have been utilised as conducting films for amperometric glucose sensing. GOx retains its bioactivity after covalent immobilisation onto dendronised pyrrole-copolymers. Amperometric response was measured as a function of glucose concentration, at a fixed potential of +0.7 V vs. Ag/AgCl in a phosphate buffered saline solution (pH 7.5). The effects of pH and temperature on storage and reusability of the amperometric glucose biosensor were investigated. Our results indicate efficient immobilisation of the enzyme onto a PAMAM type dendrimer modified surface containing a pyrrole monomer linked to a PAMAM dendron, with high enzyme loading, and increased electrode lifetime and stability.