Three- Dimensional Orientation and Localization Microscopy of Single Molecules Using Super-Resolution Imaging Technology ( Invited)

Super-resolution microscopy with nanoscale spatial resolution has become an important imaging tool in life science research. As a super-resolution technique, single-molecule localization microscopy enables us to localize, identify, and study the unique behaviors of single molecules. At the single- molecule level, the emitted fluorescence signal is highly anisotropic. Resolving the polarization or three-dimensional orientation of single fluorescent molecules is an emerging field in super-resolution microscopy. In this review, we describe the three-dimensional orientation of single molecules through super- resolution imaging techniques. These techniques include fluorescence polarization microscopy and single-molecule orientation imaging through point spread function engineering. Furthermore, we discuss other polarization super- resolution imaging approaches for the applications of live cells and single nanoparticle studies. Finally, we discuss the potential challenges and future research needs of single-molecule orientation localization microscopy. These challenges and requirements can provide in-depth insights into future research in life sciences.