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 non-toxic zirconia enhanced grafted collagen tri-helix scaffold. The formed membrane was characterized with UV–vis and FT-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 μM was constructed. Owing to the porous structure and high enzyme loading of the matrix the biosensor exhibited low limit of detection of 0.12 μM at 3σ, 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.