Multimodal interferometric imaging of nanoscale structure and macromolecular motion uncovers UV induced cellular paroxysm

We present a multimodal label-free interferometric imaging platform for measuring intracellular nanoscale structure and macromolecular dynamics in living cells with a sensitivity to macromolecules as small as 20nm and millisecond temporal resolution. We validate this system by pairing experimental measurements of nanosphere phantoms with a novel interferometric theory. Applying this system in vitro, we explore changes in higher-order chromatin structure and dynamics that occur due to cellular fixation, stem cell differentiation, and ultraviolet (UV) light irradiation. Finally, we discover a new phenomenon, cellular paroxysm, a near-instantaneous, synchronous burst of motion that occurs early in the process of UV induced cell death. Given this platforms ability to obtain nanoscale sensitive, millisecond resolved information within live cells without concerns of photobleaching, it has the potential to answer a broad range of critical biological questions about macromolecular behavior in live cells, particularly about the relationship between cellular structure and function.