An ultrasensitive D–A fluorescent probe for dual-mode uranyl detection in environmental and biological systems†

Given the escalating environmental risks posed by radioactive uranium contamination, there is an urgent demand for rapid and precise assessment of uranium levels in environmental and biological matrices. In this study, an ultrasensitive donor–acceptor fluorescent probe, TPA-BH, was developed for on-site rapid detection of uranium in both environmental samples and living systems. Owing to the synergistic effects of aggregation-induced emission (AIE), twisted intramolecular charge transfer (TICT) and specific coordination reactions, the probe achieved exceptional sensing performance: an ultra-low detection limit (0.0417 ppb, 720-fold below the WHO drinking water threshold), ultra-fast response (<1 min), and large Stokes shift (140 nm) with excellent selectivity across wide pH ranges (2–10). The probe demonstrated remarkable anti-interference capability in complex matrices while maintaining low cytotoxicity, enabling its successful application in real water analysis and live-cell imaging. Systematic investigations including photophysical characterization, real sample analysis, and recognition mechanism studies confirm the probe's potential for early warning of uranium pollution and public health risk assessment.