Research at the University of Michigan suggests creating “Teflon” versions of natural antibiotics found in frog skin can make

potential drugs better at thwarting bacterial defences leading possibly to a better antibiotic. It is all down to antimicrobial

peptides (AMPs). These are produced by most animals and they are the immune system’s early line of defence against

microbes trying to penetrate skin, mucous membranes and other surfaces. Injured or infected frog skin as well as the

linings of the human respiratory and gastrointestinal tracts responds to invading pathogens by producing large quantities of

AMPs. As well as fighting bacteria, AMPs attack viruses, fungi and even cancer cells, so drugs designed to mimic them

could have widespread medical applications.

The natural antibiotics AMPs were discovered in the 1980’s but they have some

limitations. They are easily broken down by protein-degrading proteases secreted by

bacteria. Increasing the concentration of AMPs to solve that problem can cause toxic side

effects, such as the destruction of red blood cells. It appears to happen because sticky

parts of the AMP molecule interact with the cell membrane in a harmful way. A research

team, led by biological chemist E.Neil Marsh, replaced sticky parts of the AMP molecule

with non-stick analogs. His inspiration came from the kitchen as much as the chemistry

lab: non-stick cookware is coated with fluorinated polymers, plastic-like compounds

composed of chains of carbon atoms surrounded by fluorine atoms. The

fluorine not only makes Teflon slippery, it also makes the coating inert to almost every

known chemical.

When Marsh and co-workers swapped sticky parts of their AMP molecule with non-stick,

fluorinated versions, the molecules became much more resistant to proteases. The

non-fluorinated AMPs were all degraded within 30 minutes. Under the same conditions,

the fluorinated AMP was intact after 10 hours. This should make them more

effective.

More experiments are planned in order to learn whether Teflon AMPs are also less toxic

than their stickier equivalents. If they are, and if further studies continue to point to their

promise, eventually producing large enough quantities of fluorinated AMPs for clinical

trials should be quite feasible.