Facile Electrochemical Biosensing Platform Based on Laser Induced Graphene/Laccase Electrode for the Effective Determination of Gallic Acid

In this study, a facile electrochemical biosensing platform was fabricated with Laccase (Lac) immobilized on laser-induced graphene (LIG) electrode by glutaraldehyde covalently binding for the effective determination of gallic acid (GA). The patterned graphene for the LIG electrode was prepared by a one-step laser direct writing on the polyimide film in ambient air. The sheet layer and spatial mesh structures of LIG give the prepared LIG electrode a large specific surface area and good conductivity. The oxygen enrichment and good hydrophilicity cause LIG to favor covalent crosslinking with laccase through glutaraldehyde. The electrochemical sensor of GA on the prepared electrode was determined by chronoamperometry. Results show that the current signals of the laccase electrodes had an excellent linear relationship with GA in the concentration range of 0.1-20 mmol/L with a detection limit of 0.07 mmol/L under optimized experimental conditions. The prepared GA sensor with good selectivity, regeneration, and stability can be applied to biological samples such as sweat, urine and serum without needing sample pretreatment.