An amperometric β-glucan biosensor based on the immobilization of bi-enzyme on Prussian blue-chitosan and gold nanoparticles-chitosan nanocomposite films

A novel beta-glucan biosensor was fabricated by immobilizing beta-glucanase (beta-G) with glucose oxidase (GOD) on nano-Prussian blue-chitosan (PB-CS) and gold nanoparticles-chitosan (AuNPs-CS) composites. Both the PB-CS and AuNPs_CS film were directly electrodeposited on the surface of gold electrode. The morphology of the AuNPs-CS/PB-CS nanocomposites was characterized by scanning electron microscope (SEM). The electrochemical behavior of the resulting sensor was investigated using cyclic voltammetry (CV) and amperometry. It was found that PB-CS nanocomposite exhibited an excellent electrocatalytic reduction towards hydrogen peroxide at a low applied potential window. The synergistic effect of AuNPs-CS/PB-CS nanocomposites could remarkably improve the performances of the biosensor. Under optimal conditions, the biosensor showed a wide linear range of 6.25-93.75 mu M, with a correlation coefficient of 0.9991. The sensitivity at an applied potential of 0.0 V was 100 nA mu M-1 cm(-2), with a detection limit of 1.56 mu M. The apparent Michaelis-Menten constant (K-m) was found to be 1.0 mM, showed a high affinity of the immobilizing beta-G for beta-glucan. The biosensor displayed a rapid response (within 10 s) toward beta-glucan, with a good selectivity and stability. (C) 2013 Elsevier B.V. All rights reserved.