Nanomolar pyrophosphate detection in water using a zinc-terpyridine receptor and its applications in antiproliferative and antioxidant activity

Abstract

A new fluorescent 4′-(3,4-diethoxyphenyl)-2,2′:6′,2′'-terpyridine ligand L and its 1:1 zinc complex ZnCl2L have been synthesized, characterized with the help of NMR, Mass spectroscopy, CHN analysis, and DFT study. In-situ prepared non-fluorescent ZnCl2L receptor was utilized for selective detection of pyrophosphate anion (P2O74-, PPi) in water (10 mM HEPES buffer, pH 7.4) in the vicinity of other competing analytes (10 equivalents of HPO42-, H2PO4-, CO32–, HCO3–, Cl−, OH–, Br−, CH3CO2–, F−, I-, NO3–, SO42-, SO32-, S2O32-, N3–) by employing UV–Visible spectroscopy and fluorescence “ON–OFF–ON” mechanism. ZnCl2L receptor formed a fluorescent 2:1 adduct with PPi in water during its detection at a nanomolar concentration (LOD ∼27.89 nM). The receptor is also successfully employed in low-cost PPi detection through real-time easily accessible paper strip application. Further, ZnCl2L exhibited significant cytotoxic activity against MDAMB-231 cells with an IC50 value of 53.85 µM and excellent antioxidant activity having an antioxidant percentage of 73.75%.