Construction of a bioinspired Fe3O4/N-HCS nanozyme for highly sensitive detection of GSH

The catalytic synergy of different nanomaterials is a potential technique used to develop a highly active and stable nanozyme . Here, magnetite on nitrogen-doped hollow carbon sphere (Fe 3 O 4 /N-HCS) composites were prepared through solvent thermal method and exhibited excellent oxidase and peroxidase-like catalytic activity under different pH levels. The dual enzyme-like catalyzed reaction of Fe 3 O 4 /N-HCS conformed to the typical Michaelis–Menten kinetics, and Fe 3 O 4 /N-HCS had a strong affinity for substrate 3,3′,5,5′-tetramethylbenzidine (TMB) with H 2 O 2 . The remarkable performance of the composites was achieved by the synergistic effect of Fe 3 O 4 and N-doped activated graphite carbon, which accelerated the formation of O 2 •- and •OH during the dual enzyme-like catalytic reaction . Furthermore, an effective colorimetric glutathione (GSH) sensor with a wide linear range from 0.02 µM to 250 µM and a detection limit as low as 9.3 nM was constructed based on the superior peroxidase-like activity of Fe 3 O 4 /N-HCS. The convenient colorimetric sensor monitored the content of GSH in the serum of mice, and the detection results were satisfactory, with a recovery of 96–103% and an RSD between 0.80% and 3.30%. This study discussed the internal mechanism of Fe 3 O 4 /N-HCS nanozyme and developed an efficient method for GSH detection to expand nanozyme application in bioanalysis .