Light-driven uranyl-organic frameworks used as signal-enhanced photoelectrochemical sensors for monitoring anthrax

The semiconductor-like characteristics and light absorption ability of metal-organic frameworks (MOFs) make it have the potential for photoelectrochemical sensing. Compared with composite and modified materials, the specific recognition of harmful substances directly using MOFs with suitable structures can undoubtedly simplify the fabrication of sensors. Herein, two photosensitive uranyl-organic frameworks (UOFs) named HNU-70 and HNU-71 were synthesized and explored as the novel “turn-on” photoelectrochemical sensors, which can be directly applied to monitor the biomarker of anthrax (dipicolinic acid). Both sensors have good selectivity and stability towards dipicolinic acid with the low detection limits of 1.062 and 1.035 nM, respectively, which are far lower than the human infection concentration. Moreover, they exhibit good applicability in the real physiological environment of human serum, demonstrating a good application prospect. Spectroscopic and electrochemical studies show that the mechanism of photocurrent enhancement results from the interaction between dipicolinic acid and UOFs, which facilitates the photogenerated electron transport. The combination of uranyl-organic frameworks with dipicolinic acid will enhance the photocurrent intensity to achieve the photoelectrochemical detection of dipicolinic acid. [Display omitted] •Design and synthesis of two novel light-sensitive three-dimensional uranyl-organic frameworks.•Two compounds can serve as efficient photoelectrochemical probes for dipicolinic acid.•The limit of detection can be as low as 1.035 nM with high selectivity.•The practicability of detection in real environment is further verified by human serum experiment.