Effect of metal coordination in modulating the binding interaction of an arylimidazole-derived organic chromophore with lipase

The development of reliable fluorescent probes for selectively and sensitively detecting particular analytes in biological systems, which can acid in better understanding the roles in their native contexts. Metal-complex dyes represent a family of structures that have attracted extensive attention in broad applications owing to their unique advantages, such as stable photophysical and electromagnetic properties, as well as good biocompatibility. In this work, we synthesized and characterized a fluorescent probe called THS, which untilizes diphenylamine (DPA) as a metal chelator and an arylimidazole-derived organic chromophore as a fluorescence signal reporter. A comparative assessment of responsive THS and its Zn(II) complex to lipase, an enzyme that breaks down fats, has been performed. We have evidenced the complexation of Zn(II) improved the sensing stability, signal-to-noise ratio (SNR), and selectivity of THS toward lipase. Importantly, we successfully applied the THSZn(II) complex to detect lipase in serum samples. This work provides an approach for fabricating simple and effective metal complex-based fluorescence probes and a promising application for the detection of biological analytes.