A feasible electrochemical biosensor for determination of glucose based on Prussian blue - Enzyme aggregates cascade catalytic system

The coral-like gold micro/nanostructures were formed onto carbon cloth followed by a Prussian blue (PB) electrochemical deposition to construct a highly sensitive H2O2 biosensor. The SEM image of PB/Au/CC showed the coral-like gold morphology, and EDS and XPS tests also further confirmed the successful loading of Au and PB. The electrochemical tests of PB/Au/CC displayed the electrode possessed excellent performance in sensing H2O2, which was quantified in the linear range from 0.002 to 13.97 mM at an applied potential of -0.05 V, with a sensitivity of 454.97 mu A mM(-1) cm(-2) and a detection limit of 0.5 mu M (S/N = 3). And then a convenient sensing platform was established via the cross-linking enzyme aggregates method, using PB as the mediator to realize the construction of glucose BIOSENSOR GOx(EA)@PB/Au/CC. The biosensor responded to glucose in the sensitivity of 70.76 mu A mM(-1) cm(-2) within the linear range from 0.05 to 3.15 mM with a detection limit of 10 mu M. The sensitivity was much higher than the electrode constructed by the cross-linking enzyme method (GOx@PB/Au/CC), and it was also highly selective, reproducible, and stable. Besides, the proposed biosensor was successfully applied to the glucose determination in real human serum samples, which proved its practicability. (C) 2021 Elsevier B.V. All rights reserved.