Study of electrochemical biosensor for determination of glucose based on Prussian blue/gold nanoparticles-chitosan nanocomposite film sensing interface

Abstract

A highly electroactive bilayer composite film sensing interface of Prussian blue (PB)/gold nanoparticles-chitosan (AuNPs-CS) was modified on Au electrode through electrochemical deposition and coating method followed by integrating glucose oxidase (GOx) into the interfacial matrix to fabricate a high-performance glucose biosensor. The excellent electrocatalytic ability of the PB/AuNPs-CS composite film sensing interface for H2O2 was evaluated, which has a broad linear response of 0.01–7.95 mM, with a low detection limit (LOD) 0.269 μM and a high sensitivity of 511.82 μA·mM−1·cm−2. The enhanced electrocatalytic activity of this sensing interface for H2O2 is attributed to the protection from the network CS film to PB and the synergistic effect of PB and AuNPs. Consequently, an electrochemical biosensing interface was constructed with GOx immobilized as a model enzyme. The PB/GOx-AuNPs-CS biosensing nanocomposite film was capable of a fast steady-state response time (within 2 s) and high sensitivity to glucose with a wide linear range of: 0.025–2.00 mM (R 2 = 0.99), with a sensitivity of 40.41 μA·mM−1·cm−2 and a LOD of 1.62 μM; and 2.00–6.50 mM (R 2 = 0.98), with a sensitivity of 8.90 μA·mM−1·cm−2 and a LOD of 7.16 μM. The biosensor has good anti-interference and selectivity, which provides a promising wide linear range platform for clinical blood glucose detection in the future.