A minireview of fluorescent probes for the dual detection of viscosity and pH: design and biological applications

The transformation of normal cells into cancer cells is a complex process, often accompanied by changes in the cellular microenvironment. As two key parameters of the cellular microenvironment, viscosity and pH have the potential to serve as cancer markers. Therefore, their simultaneous detection is of great significance for a more accurate understanding of cancer occurrence, development, metastasis, and treatment. To achieve dual detection of viscosity and pH, various fluorescence molecules have been designed, which can be classified into the following categories based on their sensitive sites: amine, phenolic hydroxyl, spiro-oxazolidine, and spiropyran. In addition to systematically comparing the design strategies, sensing mechanisms, and biological applications of these probes, this paper also highlights their limitations and potential future avenues of exploration. This may facilitate the design of more powerful fluorescent probes for diagnosing related diseases.