Bio-smart materials: Kinetics of immobilized enzymes in p(HEMA)/p(Pyrrole) hydrogels in amperometric biosensors

Sean Brahim, Dyer Narinesingh, Anthony Guiseppi-Elie

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


Various strategies are being pursued to confer the highly specific molecular recognition properties of bioactive molecules to the transducer action of inherently conductive polymers. We have successfully integrated inherently conductive polypyrrole within electrode-supported, UV cross-linked hydroxyethyl methacrylate (HEMA)-based hydrogels. These electroactive composites were used as matrixes for the physical immobilization of several oxidase enzymes to fabricate clinically important biosensors. Measurements were made of the amperometric responses via H2O2 oxidation for each biosensor. Apparent Michaelis constants, Km(app), for glucose oxidase immobilized in p(HEMA) membranes and in p(HEMA)/p(Pyrrole) composite membranes were 13.8 and 43.7 mM respectively compared to 33 mM in solution. The inclusion of polypyrrole in the hydrogel network increased the thermal stability of the immobilized enzyme at 60°C by 30% and 40% compared to p(HEMA) membranes and solution phase respectively. The composite also yielded larger Imax values (19 μA/cm-2) for glucose biosensors compared to similar glucose biosensors fabricated without the conducting polymer (15 μA). Km(app) values for cholesterol oxidase immobilized in the same composite films were ca. three orders of magnitude higher than the Km for the soluble enzyme. The polypyrrole component is shown to reduce diffusive transport but to confer thermal stability to these biosensors.

Original languageEnglish (US)
Pages (from-to)63-73
Number of pages11
JournalMacromolecular Symposia
StatePublished - 2002

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry


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