Individual cancer cells can be tricky to pin down for imaging. But now scientists have created a material coating that could trap them like Velcro (RSC Advances, published online February 1, 2012). The material positions macromolecules and cells for transmission electron microscopy (TEM), so scientists can peer down at their intricate molecular features.

“It's hard to make these kinds of observations when molecules and cells are moving around,” says lead investigator Deborah Kelly, PhD, an assistant professor at the Virginia Tech Carilion Research Institute in Roanoke. “By holding things in place we can watch for early events of drug therapy.”

Conventional TEM, Kelly explains, generates images by firing electrons through dry tissues in a vacuum. But unlike live samples in a liquid environment, dry cells have distorted, deformed proteins.

Kelly's collaborators at Protochips, Inc., in Raleigh, NC, got around the problem by flowing cells in solution through a nanofluidic chip maintained under the conditions needed for TEM. Applied within that device, the new coating—an affinity biofilm—can be labeled with adaptors that bind to cell surface receptors or to macromolecules of interest.

According to Kelly, the technology promises new opportunities for using TEM imaging to monitor the early stages of drug delivery. With nanometer resolution, TEM traverses the boundary between cellular and molecular imaging, revealing cell surface structures with unprecedented detail.

“We'd like to use this technology to watch how drugs penetrate into cancer cells,” Kelly says. “The advantage is that we can isolate specific cell populations that aren't contaminated with other types of cells that we're not as concerned with.”

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