CAMBRIDGE, Mass. For two decades, scientists have been pursuing a potential new way to treat bacterial infections, using naturally occurring proteins known as antimicrobial peptides (AMPs). Now, MIT scientists have recorded the first microscopic images showing the deadly effects of AMPs, most of which kill by poking holes in bacterial cell membranes.
Researchers in the laboratory of MIT Professor Angela Belcher modified an existing, extremely sensitive technique known as high-speed atomic force microscopy (AFM) to allow them to image the bacteria in real time. Their method, described in this Sunday's online edition of Nature Nanotechnology, represents the first way to study living cells using high-resolution images recorded in rapid succession.
Using this type of high-speed AFM could allow scientists to study how cells respond to other drugs and to viral infection, says Belcher, the Germeshausen Professor of Materials Science and Engineering and Biological Engineering. The new work could also help researchers understand how some bacteria can become resistant to AMPs (none of which have been approved as drugs yet).
Atomic force microscopy, invented in 1986, is widely used to image nanoscale materials. Its resolution is similar to that of electron microscopy, but unlike electron microscopy, it does not require a vacuum and thus can be used with living samples. However, traditional AFM requires several minutes to produce one image, so it cannot record a sequence of rapidly occurring events.
In recent years, scientists have developed high-speed AFM techniques, but haven't optimized them for living cells. That's what the MIT team set out to do, building on the experience of lead author Georg Fantner, a postdoctoral associate in Belcher's lab who had worked on high-speed AFM at the University of California at Santa Barbara.
How they did it: Atomic force microscopy makes use of a cantilever equipped with a probe ti
|Contact: Jen Hirsch|
Massachusetts Institute of Technology