NiPd mediated by conductive metal organic frameworks with facilitated electron transfer for assaying of H₂O₂ released from living cells

Rational modification of catalysts at electrode surface is essential and vital to regulate the electrochemically catalytic capability. In this work, we established an electrochemical interface functionalized by NiPd nanoparticles (NiPd NPs) mediated by metal–organic frameworks (MOFs) of Ni₃HHTP₂ (NiPd@Ni₃HHTP₂) towards assaying H₂O₂ in living cells. In contrast to NiPd NPs, NiPd@Ni₃HHTP₂ exhibited greatly enhanced electrocatalytic activity towards the reduction process of H₂O₂ with an onset potential of 0.10 V (vs. Ag/AgCl), as well as the current density increased by 23%. Moreover, the cathodic peak current showed a good linear relationship with H₂O₂ concentration in a wide range of 1.0 μM to 45.0 mM with a detection limit of 0.8 μM. The developed electrochemical method demonstrated good selectivity towards various potential interferences in cell system, and good reproducibility with a current deviation of 2.1% for 10 different functionalized electrodes. Eventually, the present electrochemical sensor with high selectivity and good stability was employed to monitor the levels of H₂O₂ released from living cells under oxidative stress.