A light-driven ultrafast sensor based on biocompatible solvatochromic metal-organic frameworks.

The design of fast, endurant, and biocompatible porous frameworks with solvatochromism, aimed to addressing the multiple visual sensing of chemicals, still remains a challenge. Here, we report on a solvatochromic metal-organic framework (MOF) based on cobalt and trimesic acid. We examined its solvatochromism through the solvent exchange and revealed high selectivity to water/dimethylformamide combination. The color change over 50 cycles during the solvent exchange occurs for 0.1 s, being 2 orders of magnitude faster than for existing MOFs. Despite the cobalt content, toxicity assays in vivo and in vitro revealed high biocompatibility of the MOF. The latter allowed implementing the fastest, highly-endurant and biocompatible MOF-based visual sensor of humidity in a desiccator for storage of water-sensitive goods and chemicals. Finally, for such a sensor, we demonstrated its multiple uses through remote light-driven recovery that contributes to the sustainability of this functional MOF.