Nano polyurethane-assisted ultrasensitive biodetection of H2O2 over immobilized Microperoxidase-11

Nanostructured polyurethane (PU) synthesized by an emulsion polymerization with narrow size distribution was employed for the first time directly as a novel matrix for enzyme immobilization to develop sensitively amperometric biosensors. When Microperoxidase-11 (MP-11) was selected as a model protein, the resulting hydrogen peroxide (H2O2) biosensor exhibited improved sensitivity of 29.6 mu A mM(-1) cm(-2) with quite good response time of (1.3 +/- 0.4)s and remarkable limit of detection as low as 10 pM (S/N 3) over existing protocols. A linear calibration curve for hydrogen peroxide was obtained up to 1.3 mu M under the optimized conditions with a relative low calculated Michaelis-Menten constant (K-M(app)) (1.87 +/- 0.05) mu M, which indicated the enhanced enzymatic affinity of MP-11 to H2O2 via PU. The possible interferents had negligible effect on the response current and time of the prepared biosensor. Results suggest that the PU nanoparticles (PU-NPs) with good biocompatibility and sufficient interfacial adhesion hold promise as an attractive support material for construction of ultrasensitive amperometric biosensor. (C) 2011 Elsevier B.V. All rights reserved.