A photo-electro-responsive fluorometric assay based on triazine covalent organicframework/polyoxometalate heterojunction for highly sensitive neuropathy biomarker glutam ic acid detection

Glutamic acid (Glu) is the most abundant excitatory neurotransmitter in the central nervous system, and an elevated level of Glu may indicate some neuropathological diseases. Herein, we developed a photoelectro-responsive fluorometric test strip-based peroxidase mimic activity of the triazine covalent organic framework/polyoxometalate heterojunction coated on paper for the effective luminol oxidation leading to a fluorogenic reaction and subsequently highly sensitive neuropathy biomarker glutamic acid detection. Results confirm the extensive π-electron delocalization, polarity, built-in electric field and high chemical stability for the as-prepared photo-electro-nanozyme. The increase in light harvesting and its separation and charge transfer were also confirmed by electrochemical and spectroscopic analysis. This photo-electronanonzymaticplatform revealed the sensitive detection of L-glutamic acid as a neurotransmitter in the linear range of ۵ μM to ۵۰۰ μM with a limit of detection (LOD) of ۱.۲ μM. The findings confirmed the safety and feasibility of the proposed photo-electro-nanonzymatic strategy for detecting L-Glu in biological samples as well as revealed satisfied selectivity in the presence of other biological molecules. This work opens a new insight into the development of signal-amplified test strips for point-of-care testing and disease monitoring.