Nanozyme Sensor Based on Au Nanoparticles/N-Doped Porous Carbon Composites for Biosensing

The rational construction of nanomaterials with boosted peroxidase (POD)-like activity is momentous in artificial enzyme design and biological catalytic fields. Herein, a hybrid nanozyme, gold nanoparticles/N-doped porous carbon (AuNPs/NPC), is fabricated via a supramolecular assembly-assisted pyrolysis strategy and engineered as a peroxidase mimic. In this strategy, a melamine-cyanurate supramolecular aggregate can be employed not only as a self-vanishing template to gain porous morphology but also as a nitrogen source to achieve an exceptional high N doping. The obtained NPC is then subsequently used to immobilize AuNPs via an in situ reduction approach. Benefiting from well-dispersed ultrafine AuNPs, high N content, hierarchical porous architecture, and the synergistic effect of AuNPs and NPC, the fabricated nanozyme exhibits enhanced POD-like activity, making it a potential alternative to peroxidase mimics. Besides, the AuNPs/NPC shows highly electrocatalytic properties, which could serve as a signal amplification platform for ultrasensitively detecting hydrogen peroxide (H2O2). The hybrid nanozyme-based electrochemical sensor shows a linear relationship within 0.2–7000 μM. Significantly, the sensitivity and limit of detection of the fabricated sensor are 285.9 μA mM–1 cm–2 and 67 nM, respectively. Also, this biosensor is applied to detect H2O2 in human serum samples and A549 cells with desirable results. Therefore, the present work offers a facile strategy for the fabrication of a high N-contained hybrid nanozyme to simulate the catalytic activity of natural enzymes and exhibits broad prospects in biosensing, mimicking-enzyme catalytic fields, and clinical diagnosis.