Rapid and on-site detection of copper ions in food and herbal samples via smartphone-assisted fluorescent-probe-based portable test kit

Copper ions (Cu 2+ ), as essential trace elements, play a critical role in maintaining human physiological functions. However, disordered copper homeostasis, particularly excessive Cu 2+ accumulation, has been implicated in the pathogenesis of various disorders. Moreover, the rapid advancement of modern industrial and agricultural practices has led to widespread Cu 2+ contamination in the environment and food. Consequently, the development of a multifunctional portable test kit is significant for quantifying Cu 2+ levels. In this work, a near-infrared (NIR) fluorescent probe ( ZYC ) was successfully developed for the detection of Cu 2+ in several real samples. The probe ZYC exhibited outstanding performances, including NIR emission ( λ em  = 660 nm), high selectivity and sensitivity (LOD = 11.7 nM), rapid response (30 s) and low cytotoxicity. The qualitative detection of elevated Cu 2+ levels in soil samples was successfully achieved using ZYC . Remarkably, a portable test kit was designed, allowing it to be used for the rapid and on-site detection of excessive Cu 2+ in herbs and vegetables. Furthermore, the fluorescence imaging of exogenous Cu 2+ in live MCF-7 cells, zebrafish and nude mice was successfully achieved utilizing probe ZYC . Consequently, probe ZYC provides a new method for elucidating the pathogenic mechanisms of Cu 2+ -associated diseases, while the development of a rapid and on-site Cu 2+ portable test kit provides a simple and convenient tool for monitoring food safety and environmental pollution.