Turning a bacterial weapon into a new drug delivery mechanism

The fight to survive, even among single-celled organisms, can be nasty. Some bacteria defend themselves using protein ribbons that can unfurl, punching through the membranes of other cells  as it elongates and releasing a deadly payload. New research in ACS Synthetic Biology suggests there may be a way to harness this ability to deliver drugs or integrate them into miniature devices.

In a search for methods to deliver pharmaceuticals or program cells, researchers have figured out how to package drugs, DNA and RNA into little biological pouches called vesicles. Getting them out to do their job in a cell, however, is another challenge. So, scientists have looked to a strain of paramecium that deploys hitchhiking bacteria to fight off other strains. The bacteria contain coiled protein polymers called R bodies that, once inside a target organism, unroll into tubes that puncture internal membranes to release bacterial toxins. Pamela A. Silver and Jessica K. Polka wanted to see if they could tune R bodies for potential use in cellular engineering.

The researchers found that they could control the sensitivity of R bodies, making them unfurl at higher or lower pH. Lab testing on E. coli showed the proteins could burst open 60% of bacterial cells in acidic conditions. Because they work rapidly and reversibly, the researchers say the R bodies could be used in a variety of biotechnology applications to target the delivery of molecules inside living systems. The proteins could also serve as switches in microelectromechanical systems, or MEMS.

Watch the process in action:


Read more great research in ACS Synthetic Biology.

If you have comments or questions for the author of this post, please e-mail: Axial@acs.org.