Visual ratiometric fluorescence sensing of L-lactate in sweat by Eu-MOF and the design of logic devices

[Display omitted] •MOF with Eu3+ showing a fast (5 min) ratiometric response to L-lactate.•With the increase of lactate concentration, a clear visual change of the fluorescence from red to blue.•Good selectivity and can detect L-lactate in artificial sweat with low detection limit (0.52 mM).•Utilizing the concentration, fluorescence intensity, and color, a code device designed. Using 1, 4-H2NDC as ligand and Eu as the center metal, the lanthanide MOF Eu-NDC was synthesized by hydrothermal method. The material showed a fast ratiometric response to L-lactate, and the fluorescence of the material varied from red to blue with the growth of lactate concentration, which can be used as a fluorescent sensor for L-lactate in sweat. The sensor exhibited good fluorescence stability to interfering components in human sweat and good detection limits for lactate in artificial sweat. Based on this, a visualized molecular logic gate that can monitor sweat lactate levels was constructed, and the material's characteristic of showing different colors with lactate concentration changes was used to indicate possible hypoxia during exercise, opening a new path for combining sweat lactate monitoring with smart molecular devices.