Single molecule spectrum dynamics imaging with 3D target-locking tracking

Abstract Fluorescence spectrum can provide rich physicochemical insights into molecular environments and interactions. However, imaging the dynamic fluorescence spectrum of rapidly moving biomolecules, along with their positional dynamics, remains a significant challenge. Here, we report a three-dimensional (3D) target-locking tracking-based single molecule fluorescence Spectrum Dynamics Imaging Microscopy (3D-SpecDIM), which is capable of simultaneously capturing both the rapid 3D positional dynamics and the physicochemical parameters changing dynamics of the biomolecules with enhanced spectral accuracy, high spectral acquisition speed, single-molecule sensitivity, and high 3D spatiotemporal localization precision. As a demonstration, 3D-SpecDIM is applied to real-time spectral imaging of the mitophagy process, showing its enhanced ratiometric fluorescence imaging capability. Additionally, 3D-SpecDIM is used to perform multi-resolution imaging, which provides valuable contextual information on the mitophagy process. Furthermore, we demonstrated the quantitative imaging capability of 3D-SpecDIM by imaging the cellular blebbing process. By continuously monitoring the physicochemical parameter dynamics of biomolecular environments through spectral information, coupled with 3D positional dynamics imaging, 3D-SpecDIM offers a versatile platform for concurrently acquiring multiparameter dynamics, providing comprehensive insights unattainable through conventional imaging techniques. 3D-SpecDIM represents a substantial advancement in single-molecule spectral dynamics imaging techniques.