Transition metal complexes as optical probes for super-resolution microscopy.

The suite of techniques encompassing optical super-resolution microscopy can facilitate detailed visualization of biological structures and biochemical transformations at unprecedented levels of resolution and contrast; however, they depend on imaging probes with specific biophysical and photophysical properties. In this context, metal complexes with tuneable photo-excited states and stability towards photobleaching are promising candidates for advanced imaging techniques. This Review illustrates how, by selecting appropriate optical properties and luminescence responses, metal complexes can be utilized as probes for a range of super-resolution microscopy techniques, including multimodal imaging, to study subcellular architecture and dynamics with nanoscale resolution. Limitations and challenges of the existing molecular probes are also discussed. By highlighting these recent innovations and providing suggestions for future directions, this Review further underscores the importance of optical probes in pushing the boundaries of super-resolution microscopy and advancing our understanding of complex biological systems.