Emerging rules for effective antimicrobial coatings

• Microbial biofilms can cause implant failure and are difficult to treat.
• Antimicrobial peptides hold promise as surface active antimicrobial agents.
• Multifunctional coatings with different architectures are available.
• Standardized in vitro and in vivo testing procedures are needed to evaluate coatings.

In order to colonize abiotic surfaces, bacteria and fungi undergo a profound change in their biology to form biofilms: communities of microbes embedded into a matrix of secreted macromolecules. Despite strict hygiene standards, biofilm-related infections associated with implantable devices remain a common complication in the clinic. Here, the application of highly dosed antibiotics is problematic in that the biofilm (i) provides a protective environment for microbes to evade antibiotics and/or (ii) can provide selective pressure for the evolution of antibiotic-resistant microbes. However, recent research suggests that effective prevention of biofilm formation may be achieved by multifunctional surface coatings that provide both non-adhesive and antimicrobial properties imparted by antimicrobial peptides. Such coatings are the subject of this review.