Hybrid fluorophores-based fluorogenic paper device for visually high-throughput detection of Cu²⁺ in real samples

Paper-based diagnostic assay is quite popular in point-of-care testing (POCT). In this work, we reported a series of hybrid fluorophores based on fluorescein derivatives and investigated their fluorescent properties in detail. To extend the practical application of these hybrid fluorophores, we further constructed the corresponding probes (FN1-FN4) for Cu²⁺ detection. In comparison with the other three probes, FN4 showed high selectivity and sensitivity, as well as response to Cu²⁺ within 20 min. Particularly, by introducing this probe into the paper-based device, we could achieve simple, high-throughput, visual and highly sensitive platform for POC detection of Cu²⁺. Finally, we assessed the paper-based device in real samples such as serum, cytochylema and lake water to demonstrate its promising application. As a result, satisfied performance for Cu²⁺ detection was achieved, which indicates the great potential of our strategy in the construction of POCT system for detecting analytes.