Anti-bacterial implants

Biomaterial-associated infection (BAI) in implant devices is caused by biofilm formation mainly of Staphylococcus aureus and coagulase-negative staphylococci. BAI is very difficult to treat with antibiotics and alternative approaches are urgently needed to combat such infections.

The scope of the EU-funded BALI (Biofilm alliance) project is to provide a solution to BAI by combining highly innovative technologies. The consortium aims to generate synthetic antimicrobial and anti-biofilm peptides (SAAP) along with a release system for application of coating to the surface of biomaterials.

Researchers used the synthetic OP-145 peptide, because of its potent anti-inflammatory, antimicrobial and anti-biofilm activity, as the basis to derive other candidate peptides. The human blood platelet antimicrobial protein Thrombocidin-1 has also served as the starting template for SAAP synthesis. Ten peptides have been tested so far to assess their capacity to kill a wide spectrum of gram-positive and -negative bacteria.

Insight into the mode of action of these SAAPs indicate that on top of their ability to prevent biofilm formation, they exhibit strong anti-inflammatory activity. In vitro experiments also showed that OP-145 affects the integrity of both bacterial and mammalian membranes.

To achieve controlled release of SAAPs, scientists employed the PolyPid polymer-lipid-based drug delivery platform. Following extensive optimisation to make it suitable for coatings, it has successfully been used to cover implants in various animal models. Upon challenge with S.aureus, SAAPs prevented infection in these animals clearly demonstrating its clinical potential.

The consortium is confident that apart from preventing biofilm formation, this approach will also reduce the development of antimicrobial resistance. Considering the increasing number of hip fractures in Europe, the BALI method is anticipated to reduce infection risk as well as operative and hospitalisation costs.