Graphitic C6N6-supported Dual Cu/Zn SAzymes Mimicking Allosteric Regulation for Intelligent Switching Biosensing

Self-adaptability is highly envisioned for artificial devices such as robots with chemical noses. To this end, seeking catalysts with reversibly switchable functions is promising but generally hampered by mismatched specific valence state of active centers for a certain type of catalytic activity. Herein, we report a graphitic C6N6-supported dual Cu/Zn single-atom nanozyme (Cu/Zn-C6N6) with switchable functions triggered by light irradiation. Cu/Zn-C6N6 exhibited highly efficient distinctive superoxide dismutase (SOD)- and peroxidase-like (POD) activity under dark and light, respectively. Moreover, such switch between SOD- and POD-like activities were reversible by alternating dark and light irradiation with an efficiency more than 90%. The comprehensive experimental and TD-DFT calculations disclosed that both illumination and the Cu/Zn doping ratio modulate the reduction potential (φred) by altering the potential energy surface and frontier orbital energies, thereby fine-tuning the SOD activity, making distinctive SOD- and POD-like activities originated from the same active center (Cu-Nx) but with different valence states, triggered by photoreduction. As a proof-of-concept application, Cu/Zn-C6N6 was further confined to a microfluidic chip and applied to an intelligent single-interface biosensor with reversibly switched ability in detecting xanthine and glucose in vitro.