Effect of Acridine Orange on Improving the Electrochemical Performance of Tyrosinase Adsorbed Sulfide Minerals Based Catechol Biosensor

A highly sensitive and selective electrochemical biosensor for catechol (CC) detection was developed by immobilizing tyrosinase (TYR) on a glassy carbon electrode (GCE) modified with sulfide minerals (SFMs) in the co-adsorption of acridine orange (AO). The sensor employed natural SFMs as the substrate material and utilized AO as a molecular recognition probe to create synergy effect for TYR to detect catechol. The developed TYR/AO/SFMs/GCE biosensors were characterized by scanning electron microscope, energy dispersive analysis of X-rays spectroscopy, X-ray diffraction spectra, X-ray fluorescence, and electrochemical analysis. The results show that the sensors have excellent electrochemical activity for the detection of catechol (CC) under optimized conditions. The linear ranges were 0.1-50 mu M, 0.1-10 mu M, 0.1-50 mu M and 0.1-100 mu M for galena, pyrite, chalcopyrite and sphalerite, respectively, with the detection limits of 1.18 mu M, 0.29 mu M, 0.54 mu M and 0.68 mu M, respectively. The sensors also have good reproducibility, stability, repeatability and anti-interference ability. AO is essential to increase the adsorbed amount and provides suitable orientation of the adsorbed TYR on these sulfide minerals' surfaces. In consideration of cost-effective and rich resources of sulfide minerals, easily physical adsorption method, combination of organic dye, minerals and enzymes, this strategy paves a new way to design other novel electrochemical biosensors.