Synthesis of Highly Selective Magnetite (Fe3O4) and Tyrosinase Immobilized on Chitosan Microspheres as Low Potential Electrochemical Biosensor

Abstract

In this work, a new biosensor using electrochemical magnetic loading of Tyrosinase (Tyr) immobilized on chitosan microspheres via in situ hybridization with Fe3O4 (Chitosan@Fe3O4) was developed. Fe3O4 was used to reduce the applied potential while chitosan microspheres helped in keeping the affinity with enzyme. The magnetic microspheres were characterized by scanning electron microscopy, Energy dispersive spectroscopy and Fourier transform Infra-red spectroscopy. These microspheres were confirmed to possess high electron transport performance of −50 mV. Parameters affecting the biosensor response such as amount of modifying material, pH, applied potential and temperature were optimized. The biosensor selectively detected catechol in a linear range from 2.64 × 10−6 M to 8.4 × 10−5 M at a sensitivity of 14.72 μA/mM with a limit of detection of 0.79 μM and a Michaelis–Menten constant (Km app ) of 14.3 μM. The proposed design possesses attributes like cost effectiveness, ease of recycling and high selectivity in bio-sensing and thus can be deemed as a promising approach for commercial level biosensor synthesis.