Antifungal surfaces go 3D

We have continued our investigation on coatings that could be used to combat deadly fungal infections. Implanted medical devices can become colonised by the fungal yeast Candida albicans despite sterilisation procedures. Therefore, a medical device with a surface modification that could kill Candida on contact may help to reduce infection and death from these infections.

Previously we have shown that the antifungal drug caspofungin can be attached to medical-grade plastics using an ultra-thin surface layer only 20 nm thick. Because this coating is thin and flat, the caspofungin molecules essentially form a flat layer (approximately a 2 dimensional surface).

Our latest research has investigated the possibility of instead attaching caspofungin on polymer brushes. This allows the drug to be presented on flexible polymer linkers, extending hundreds of nanometres from the surface, and would improve the way the drug interacts with the fungal cell wall.

Depiction of the reaction steps, combining plasma polymerization and ARGET-ATRP to covalently attach amine-containing drugs, such as caspofungin, to surface-grafted PHEMA.

This is an important advancement in helping us to understand how surface-immobilised drugs interact with the fungal cell wall. We will use this information to understand how antibiotics work mecahanistically – that is, how tethered drugs would be able to penetrate into the cell wall and find their target of action which ends up killing the cell. Finding new mechanisms of action for antibiotic drugs could be one way that we can find new uses for a dwindling supply of effective antibiotic agents.

The work has been published in the journal Biointerphases and is an “Editor’s Pick”. This article is freely accessible through open access publishing.

We gratefully acknowledge the Australian Research Council for funding. (Discovery Project DP150101674. “Combating fungal biofilm growth on surfaces”.)