▎ 摘　　要

The cost effective synthesis of ultrasensitive micro-electrodes with excellent biocompatibility, conductibility, specific surface area, long-term stability and flexibility is a challenge in diverse portable sensing electronics device. Herein, a flexible nanogold modified graphene-based porous electrode with exceptionally powerful loading capacity and electro-conductibility was developed through the laser-scribing, dipping, and electro-deposition processes. Benefited from laser-induced photothermal conversion, the graphene-based electrode presented three-dimensional framework structure with abundant oxygen-containing groups and nitrogen doping, which improved electron transport and superficial area. Further performance enhancements of the electrode were enabled by mild organic acids/alcohols-catalyzed chemically reduction and nanogold electro-deposition. The resistance of the functionalized graphene-based electrode decreased by 3.9 times and the specific surface area increased by 2.5 times compared with the original laser-induced graphene. The corresponding mechanism was investigated systematically. Based on the prepared electrodes, a flexible electrochemical sensing chip integrating Cu2+-assembled reticular-structured signal label and Zn2+-activated DNAzyme was constructed for quantitative detecting Cu2+ and Zn2+, which presented low detection limit of 0.32 nM (Cu2+) and 0.34 nM (Zn2+), excellent stability and flexibility. The investigation reveals that the dipping treatment and nanogold electrodeposition for porous laser-induced graphene are the promising approaches for the flexible electrochemical sensing applications.