3D coral-like gold/carbon paper electrode modified with covalent and cross-linked enzyme aggregates for electrochemical sensing of glucose

The three-dimensional (3D) coral-like gold/carbon paper (Au/CP) electrode was prepared by a simple one-step electrodeposition procedure assisted by hydrogen evolution without any additive, and used as a support of glucose oxidase (GOx). GOx was immobilized onto the 3D porous electrode Au/CP in a process combining covalent attachment and cross-linking enzyme aggregates to fabricate the biosensor GOx_EA-Au/CP. The structure and electrochemical properties of prepared electrodes were tested and characterized by scanning electron microscopy (SEM), chronocoulometry, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The gold coating with coral-like morphology can be found on the Au/CP surface, and the biosensor we fabricated exhibits high sensitivity (96.27 μA mM⁻¹ cm⁻²) to glucose with a considerably wide linear response range (0.002–21.97 mM) as well as a low detection limit (0.6 μM) for glucose detection. In human serum samples, the detection of glucose based on this sensor has high detection stability and recovery, which means the as-prepared electrode is expected to be served as a competitive candidate for developing enzymatic glucose biosensors.