Hydrogen peroxide biosensor based on hemoglobin modified zirconia nanoparticles-grafted collagen matrix

A novel method for the immobilization of hemoglobin (Hb) and preparation of reagentless biosensor was proposed using a biocompatible nontoxic zirconia enhanced grafted collagen tri-helix scaffold. The formed membrane was characterized with UV-vis and Fr-IR spectroscopy, scanning electron microscope and electrochemical methods. The Hb immobilized in the matrix showed excellent direct electrochemistry with an electron transfer rate constant of 6.46 s(-1) and electrocatalytic activity to the reduction of hydrogen peroxide. The apparent Michaelis-Menten constant for H2O2 was 0.026 mM, showing good affinity. Based on the direct electrochemistry, a new biosensor for H2O2 ranging from 0.8 to 132 mu M was constructed. Owing to the porous structure and high enzyme loading of the matrix the biosensor exhibited low limit of detection of 0.12 mu M at 3 sigma, fast response less than 5 s and high sensitivity of 45.6 mA M-1 cm(-2). The biosensor exhibited acceptable stability and reproducibility. ZrO2-grafted collagen provided a good matrix for protein immobilization and biosensing preparation. This method was useful for monitoring H2O2 in practical samples with the satisfactory results. (c) 2006 Elsevier B.V. All rights reserved.