摘要
Nanozyme possesses multiple advantages including low cost, high stability, easy manufacture, and versatility, which have earned interest in the application of biomedical purposes. Herein, the nitrogen-graphene quantum dot (N-GQDs) decorated mixed molybdenum oxides (MMO, MoOx, 2 < x < 3) were hydrothermally fabricated to serve as the peroxidase-like nanozymes for the ultrasensitive detection of neurofilament light chain (NfL). The kinetics parameters of nanozyme including maximum velocity (Vmax) and Michaelis-Menten half-saturation constant (Km) were examined and compared with natural horseradish peroxidase (HRP). In addition, the detection principle of MMO/N-GQD-based immunosensor was established. Results show that addition of N-GQDs can trigger the electron flow from N-GQDs to MMO, making the redox center of Mo elements more effective on electron transfer. The MMO/N-GQDs/PPL/anti-NfL immunosensor exhibits excellent analytical performance on NfL detection with both UV–visible spectrophotometer or smartphone-oriented RGB reader. A linear range of 16–1000 pg mL− 1 with a limit of detection of 2.24 pg mL− 1 and recovery of 83 – 104 % in human serum is achieved. The immunosensor can attain a selectivity coefficient of higher than 0.7 against interferences containing common ions, amino acids, cholesterol, and biomarkers in serum. Results corroborate that the greensynthesized peroxidase-like MMO/N-GQD possesses the advantages of cost-effective and high scalability, which can serve as a potential nanozyme to replace natural enzyme for the ultrasensitive and selective detection of serum NfL with superior recovery in human serum.