Label-free imaging of the native, living cellular nanoarchitecture using partial-wave spectroscopic microscopy

Luay M. Almassalha, Greta M. Bauer, John E. Chandler, Scott Gladstein, Lusik Cherkezyan, Yolanda Stypula-Cyrus, Samuel Weinberg, Di Zhang, Peder Thusgaard Ruhoff, Hemant K. Roy, Hariharan Subramanian, Navdeep S. Chandel, Igal Szleifer, Vadim Backman*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


The organization of chromatin is a regulator of molecular processes including transcription, replication, and DNA repair. The structures within chromatin that regulate these processes span from the nucleosomal (10-nm) to the chromosomal (>200-nm) levels, with little known about the dynamics of chromatin structure between these scales due to a lack of quantitative imaging technique in live cells. Previous work using partial-wave spectroscopic (PWS) microscopy, a quantitative imaging technique with sensitivity to macromolecular organization between 20 and 200 nm, has shown that transformation of chromatin at these length scales is a fundamental event during carcinogenesis. As the dynamics of chromatin likely play a critical regulatory role in cellular function, it is critical to develop live-cell imaging techniques that can probe the real-time temporal behavior of the chromatin nanoarchitecture. Therefore, we developed a live-cell PWS technique that allows high-throughput, label-free study of the causal relationship between nanoscale organization and molecular function in real time. In this work, we use live-cell PWS to study the change in chromatin structure due to DNA damage and expand on the link between metabolic function and the structure of higher-order chromatin. In particular, we studied the temporal changes to chromatin during UV light exposure, show that live-cell DNA-binding dyes induce damage to chromatin within seconds, and demonstrate a direct link between higher-order chromatin structure and mitochondrial membrane potential. Because biological function is tightly paired with structure, live-cell PWS is a powerful tool to study the nanoscale structure-function relationship in live cells.

Original languageEnglish (US)
Pages (from-to)E6372-E6381
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number42
StatePublished - Oct 18 2016


  • Cell dynamics
  • Chromatin
  • DNA damage
  • Microscopy
  • Mitochondrial metabolism

ASJC Scopus subject areas

  • General


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