Molecular rotor-based probes for protein monitoring in biomedical research

As the fundamental executors of biological function, proteins are frequently dysregulated or differentially expressed in disease states, making them valuable biomarkers and/or therapeutic targets. Conventional approaches to monitoring the presence and activity of these proteins - including enzyme-linked immunosorbent assay, western blotting and mass spectrometry - have limited ability to provide real-time information on living cells. Fluorescence imaging overcomes these limitations by enabling selective, non-invasive and dynamic protein analysis. Molecular rotor fluorophores offer unique advantages owing to their high sensitivity to microenvironmental changes and tunable photophysical properties. Notably, these molecular rotor scaffolds can be functionalized into targeting probes that become highly emissive upon binding to specific proteins via the restriction of intramolecular rotation. Here, we introduce molecular rotor-based probes and outline their design principles and detection mechanisms. We highlight their applications in disease diagnosis and biological research, and we discuss the current challenges and prospects for clinical translation.