An antibiotic that can be switched on and off with light!

In a breakthrough, scientists have produced an antibiotic whose biological activity can be controlled with light - opening up new options in treating bacterial infections as side effects can be minimised by switching.

Thanks to the robust diarylethene photoswitch, the anti-microbial effect of the peptide mimetic can be applied in a spatially and temporally specific manner.

Photoswitchable molecules modify their structure and properties when exposed to light of an adequate wavelength.

Among the photoswitches known are diarylethenes.

By reversible photoisomerization - a reversible light-induced internal relocation of the molecule - the open form is turned into a closed (inactivated) form.

Professor Anne S. Ulrich from Karlsruhe Institute of Technology (KIT) in Germany, along with researchers from University of Kiev, produced a photoswitchable peptide mimetic based on a diarylethene scaffold that can be photoisomerised reversibly.

The team then treated a bacterial film with the inactivated antibiotic and exposed it to light via a mask.

As a result, the photoswitchable diarylethene was converted from a closed into an open form.

Due to the structural modification induced, the entire substance molecule had a much higher anti-microbial effect.

"In the future, such photoactivable antibiotics might be used as smart therapeutic agents against local bacterial infections," Ulrich explained.

Based on this strategy, new peptide-based agents against cancer might be feasible as the newly developed photoactivable building block can also be applied in other peptide sequences.

The research was published in the journal Angewandte Chemie.