Strategic design of self-disassembling Co-PDI fluorescent architecture for dual detection of ascorbic acid and alkaline phosphatase in biological systems

Alkaline phosphatase (ALP) serves as a crucial biomarker in clinical diagnostics, where its activity levels directly correlate with various pathological conditions. In this work, we present a rationally designed fluorescence sensing platform based on a cobalt-perylene diimide (Co-PDI) metal-organic coordination complex that exhibits red emission for the simultaneous detection of ascorbic acid (AA) and ALP activity. The sensing mechanism operates through competitive coordination between AA and PDI ligands at Co²⁺ binding sites. This competition triggers the release of PDI molecules, which subsequently form aggregates at high concentrations, leading to fluorescence quenching. Through systematic optimization, the system demonstrates high selectivity and sensitivity for both AA and ALP detection. To enhance practical applicability, we developed a smartphone-integrated detection platform, enabling real-time visual monitoring of analytes. The practical efficacy of this sensing system was validated through extensive testing in complex biological matrices, including cancer cell lysates, liver fibrosis mouse serum, and raw milk samples. The platform successfully detected elevated ALP expression in both liver cancer cells and fibrotic mouse serum. This robust sensing platform offers a promising tool for precise ALP quantification in complex biological environments, potentially facilitating early disease diagnosis and monitoring.