Triple-channel visualization of uric acid in human urine: A probe based on triple-emissive cyan carbon dots

The study pioneered a triple-channel fluorescence detection method for highly sensitive measurement of uric acid (UA), in which triple-emissive cyan carbon dots (TCDs) were adopted as the fluorescent probe. The TCDs exhibited three emission peaks at 346, 417, and 511 nm upon 300 nm excitation. Notably, the introduction of UA resulted in a clear and varied quenching of TCDs fluorescence across all three emission channels, thereby establishing a triple-channel sensing paradigm for UA detection. The probe demonstrated a linear response over a broad concentration range of 0.0-450.0 μM, with an ultralow detection limit (LOD) of 0.054 μM. Remarkably, the vivid fluorescence color transition from cyan to blue enabled the construction of a portable smartphone-assisted sensing platform and disposable test paper device, achieving LODs of 2.20 and 5.61 μM, respectively. Moreover, these multi-mode sensing platforms have been successfully employed for the determination of UA in human urine samples, achieving satisfactory analytical results. This work highlights the great promise of triple-emissive CDs as multi-channel visual probes, constituting a remarkable advance for on-site UA monitoring in practical applications.