Reagentless Electrochemical Hydrogen Peroxide Biosensor Based on Toluidine Blue-Derived Organic Material and Functionalized Gold Nanoparticles

Abstract

In this paper, a biosensor was proposed. At first, an organic conductive material, 3,4,9,10-perylenetetracarboxylic acid-toluidine blue (PTATB), was synthesized by 3,4,9,10-perylenetetracarboxylic dianhydride and toluidine blue. Then the prepared PTATB was dispersed into solution and dropped on a glassy carbon electrode to form a stable composite film with efficient redox activity. Later, gold nanoparticles (GNPs) were carbonylated by -carboxymethyl chitosan (CMCS) to obtain functionalized gold nanoparticles (CMCS-GNPs), which were adsorbed on the film with positive charge via electrostatic interaction. Finally, hemoglobin, as a model enzyme, was covalently immobilized onto the electrode modified with matrix to construct a new biosensor. The proposed biosensor displays a high sensitivity, fast analytical time, and broader linear response to in the range from to with a limit of detection of at 3 times the background noise. The apparent Michaelis–Menten constant and the maximum current density for the proposed biosensor were estimated to be 0.62 mM and , respectively. This work provided a new avenue for the electrochemical investigation of enzyme immobilization.