High-precision colorimetric-fluorescent dual-mode biosensor for detecting acetylcholinesterase based on a trimetallic nanozyme for efficient peroxidase-mimicking

Highly sensitive and stable acetylcholinesterase detection is critical for diagnosing and treating various neurotransmission-related diseases. In this study, a novel colorimetric-fluorescent dual-mode biosensor based on highly dispersive trimetal-modified graphite-phase carbon nitride nanocomposites for acetylcholinesterase detection was designed and synthesized by phosphorus doping and a mixed-metal MOF strategy. The specific surface area of trimetal-modified graphite-phase carbon nitride nanocomposites increased from 15.81 to 96.69 g m-2 , and its thermal stability, interfacial charge transfer, and oxidation-reduction capability were enhanced compared with those of graphite-phase carbon nitride. First-principles density functional theory calculations and steady-state kinetic analysis are applied to investigate the electronic structures and efficient peroxidase-mimicking properties of trimetalmodified graphite-phase carbon nitride nanocomposites. The oxidation of 3,3' ,5,5' -tetramethylbenzidin was inhibited by thiocholine, which originates from the decomposition of thiocholine iodide by Acetylcholinesterase (AChE), resulting in changes in fluorescence and absorbance intensity. Due to the independence and complementarity of the signals, a highly precise colorimetric-fluorescent dual-mode biosensor with a linear range for detecting AChE of 4-20 mu U mL-1 and detection limits of 0.13 mu U mL-1 (colorimetric) and 0.04 mu U mL-1 (fluorescence) was developed. The spiking recovery of AChE in actual samples was 99.0 %-100.4 %. Therefore, a highly accurate, specific, and stable dual-mode biosensor is available for AChE detection, and this biosensor has the potential for the analysis of other biomarkers. (c) 2024 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.