Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA.
Department of Molecular Biosciences, Northwestern University, Evanston, IL, 60208, USA.
Nat Commun. 2019 Apr 10;10(1):1652. doi: 10.1038/s41467-019-09717-6.
Understanding the relationship between intracellular motion and macromolecular structure remains a challenge in biology. Macromolecular structures are assembled from numerous molecules, some of which cannot be labeled. Most techniques to study motion require potentially cytotoxic dyes or transfection, which can alter cellular behavior and are susceptible to photobleaching. Here we present a multimodal label-free imaging platform for measuring intracellular structure and macromolecular dynamics in living cells with a sensitivity to macromolecular structure as small as 20 nm and millisecond temporal resolution. We develop and validate a theory for temporal measurements of light interference. In vitro, we study how higher-order chromatin structure and dynamics change during cell differentiation and ultraviolet (UV) light irradiation. Finally, we discover cellular paroxysms, a near-instantaneous burst of macromolecular motion that occurs during UV induced cell death. With nanoscale sensitive, millisecond resolved capabilities, this platform could address critical questions about macromolecular behavior in live cells.
理解细胞内运动与生物大分子结构之间的关系仍然是生物学领域的一项挑战。生物大分子结构是由众多分子组装而成的，其中一些分子无法被标记。大多数研究运动的技术都需要潜在细胞毒性的染料或转染，这可能会改变细胞行为，并且容易发生光漂白。在这里，我们提出了一种多模态无标记成像平台，用于测量活细胞内的结构和生物大分子动力学，对生物大分子结构的灵敏度低至 20nm，时间分辨率为毫秒级。我们开发并验证了一种用于光干涉时间测量的理论。在体外，我们研究了细胞分化和紫外线（UV）照射过程中高级染色质结构和动力学如何变化。最后，我们发现了细胞爆发，即在 UV 诱导的细胞死亡过程中发生的一种瞬间的生物大分子运动爆发。该平台具有纳米级的灵敏度和毫秒级的分辨率，能够解决关于活细胞中生物大分子行为的关键问题。
