A fundamental challenge in molecular cell biology is resolving nano- and molecule-scale dynamic events within their native environments, as these processes are key to understanding how cells organize, adapt, and sustain life. Intracellular transport, for example, is a highly dynamic and multifactorial process shaped by the properties of the cargo, its geometric environment within the spatially heterogeneous cellular milieu, and the biochemical state of the cell. Such complexities make the optical approach an ideal choice toward addressing this outstanding problem which introduces minimum perturbation to a live cell; yet, popular imaging methods tend to fall short of fully capturing the fast nanoscale dynamics in 3D or to place the observations in context. One unconventional solution is the multiresolution imaging concept, which captures dynamics of the object of interest with nanometer-scale spatial and microsecond temporal resolutions while concurrently recording larger-scale contextual information about the surrounding cellular environment. Here, as the latest implementation of the idea, we present a time-resolved multiresolution dynamics imaging platform. It combines lifetime-gated active-feedback 3D tracking of individual nanoparticles (∼8 nm spatial and 10 μs temporal resolution) with hardware-synchronized acquisition of multidimensional environmental data across broad spatial and temporal scales. This platform enables simultaneous measurements of nanoscale motion and large-scale cellular context in real time. Using the time-resolved multiresolution 3D imaging, we quantitatively measured transport behaviors and classified them into distinct modes of movement, revealing distinct patterns of cargo activity that correlate with cellular state. By bridging high-resolution tracking with contextual mapping, the multiresolution concept provides a niche yet powerful framework for understanding nanoscale motion in live cells, and has the potential to open up new avenues for the direct study of regulating sub-millisecond transport dynamics on the molecule- and nano-scales and how it is related to disease-related dysfunctions.
Zhao et al. (Sun,) studied this question.