Fabrication of CoNPs-embedded porous carbon composites based on morphochemical imprinting strategy for detection of H2O2 released from living cells

Highlights: • First demonstration of CoNPs-embedded N-doped porous carbon microspheres (Co@NCS) for H₂O₂ sensing. • Supramolecular melamine cyanurate aggregates were used as morphology and chemical feature dual-imprinting template. • The prepared Co@NCS possesses high surface area and hierarchical pore structure. • The Co@NCS sensor was successfully used for detecting H₂O₂ released from living cells. -- Abstract: Rational construction of biosensor to determine reactive oxygen species (ROS) generated from living cells is one of the great challenges in physiological and pathological fields. Herein, for the first time, a novel Co nanoparticles (CoNPs) embedded walnut-like N-doped porous carbon microsphere (Co@NCS) can be synthesized using dual imprinting strategy by pyrolysis and acid leaching. The distinct morphology and chemical characteristic of melamine cyanurate (MC) aggregates can be imprinted in the carbon source derived from glucose during the pyrolysis process. According to our research, with synergistic effect of CoNPs and NCS, the Co@NCS shows an excellent electrochemical activity toward the reduction of hydrogen peroxide (H₂O₂). The Co@NCS modified electrode exhibits a wider linear detection response with the range from 0.5 μM to 7500 μM and a low detection limit of 88 nM (S/N = 3). Moreover, with desirable selectivity, decent reproducibility and satisfied anti-interference performance, the fabricated biosensor can be applied to determine H₂O₂ in human serum samples and that released from living cell, indicating the potential applications in the fields of pathological and physiological sensing.