New imaging technique peers inside living cells

To undergo high-resolution imaging, cells often must be sliced and diced, dehydrated, painted with toxic stains, or embedded in resin. For cells, the result is certain death.

But if researchers can only view the inner workings of dead cells, they're only seeing part of the story. They cannot monitor living cells' dynamic real-time processes, such as metabolic reactions or responses to diseases or treatments.
"Sub-cellular components and structures have a profound influence on the behavior of the complex cellular machinery and systems biology," said Northwestern University's Gajendra Shekhawat. "However, unraveling the structures and components inside the cell is very challenging because they are so fragile."

Now Shekhawat and Vinayak P. Dravid, the Abraham Harris Professor of Materials Science and Engineering at Northwestern Engineering, have developed a novel non-invasive imaging system that makes it possible to view the sub-cellular architecture of live cells at nanometer-scale resolution. Called Ultrasound Bioprobe, the technique combines ultrasound waves with atomic force microscopy, interacting with live cells to determine the changes in their mechanical behavior.

Supported by the National Science Foundation (NSF) and the National Heart, Lung, and Blood Institute, the research was recently published in Science Advances. Shekhawat and Dravid served as the paper's co-corresponding authors. Shekhawat, a research associate professor in materials science and engineering, was also the first author of the paper. The research was completed in the Northwestern University Atomic and Nanoscale Characterization Experimental (NUANCE) Center. NUANCE is the lead facility in the NSF-supported National Nanotechnology Coordinated Infrastructure (NNCI) Program, which is headquartered at Northwestern and called the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource.