Synthesis and characterization of semiconducting polypyrrole/polyacrylamide microparticles with GOx for biosensor applications

Polypyrrole has been synthesized by the incorporation of the sulfonate dopant anion that renders the polymer dispersed in water. Polypyrrole was incorporated in the aqueous phase of a water in oil (W/O) concentrated emulsion, together with different amounts of the acrylamide monomer and the crosslinker bisacrylamide. The polymerization of the aqueous dispersed phase produces microparticles with average size 4.5 μm in which polypyrrole is entrapped. The conductivity of the microparticles with 50/50 (w/w) polypyrrole/polyacrylamide is 1 × 10−5 S/cm, in the range of semiconductor materials. Glucose Oxidase (GOx) was immobilized in the microparticles by incorporating the enzyme into the aqueous phase of the concentrated emulsion before starting polymerization. The microparticles with the immobilized enzyme were used as biological component of an amperometric glucose sensor that responds to glucose under both aerobic and anaerobic conditions, demonstrating the effectiveness of the immobilization technique as well as a possible application of the semi-conducting microparticles.