Therapeutic Potential of Antimicrobial Peptides in Polymicrobial Biofilm-Associated Infections

It is widely recognized that many chronic infections of the human body have a polymicrobial etiology. These include diabetic foot ulcer infections, lung infections in cystic fibrosis patients, periodontitis, otitis, urinary tract infections and even a proportion of systemic infections. The treatment of mixed infections poses serious challenges in the clinic. First, polymicrobial communities of microorganisms often organize themselves as biofilms that are notoriously recalcitrant to antimicrobial therapy and clearance by the host immune system. Secondly, a plethora of interactions among community members may affect the expression of virulence factors and the susceptibility to antimicrobials of individual species in the community. Therefore, new strategies able to target multiple pathogens in mixed populations need to be urgently developed and evaluated. In this regard, antimicrobial or host defense peptides (AMPs) deserve particular attention as they are endowed with many favorable features that may serve to this end. The aim of the present review is to offer a comprehensive and updated overview of studies addressing the therapeutic potential of AMPs in mixed infections, highlighting the opportunities offered by this class of antimicrobials in the fight against polymicrobial infections, but also the limits that may arise in their use for this type of application.     

Integrated three‐dimensional fiber/hydrogel biphasic scaffolds for periodontal bone tissue engineering

Combining a tissue engineering scaffold made of a load‐bearing polymer with a hydrogel represents a powerful approach to enhancing the functionalities of the resulting biphasic construct, such as its mechanical properties or ability to support cellular colonization. This research activity was aimed at the development of biphasic scaffolds through the combination of an additively manufactured poly(?‐caprolactone) (PCL) fiber construct and a chitosan/poly(γ‐glutamic acid) polyelectrolyte complex hydrogel. By investigating a set of layered structures made of PCL or PCL/hydroxyapatite composite, biphasic scaffold prototypes with good integration of the two phases at the macroscale and microscale were developed. The biphasic constructs were able to absorb cell culture medium up to 10‐fold of their weight, and the combination of the two phases had a significant influence on compressive mechanical properties compared with hydrogel or PCL scaffold alone. In addition, due to the presence of chitosan in the hydrogel phase, biphasic scaffolds exerted a broad‐spectrum antibacterial activity. The developed biphasic systems appear well suited for application in periodontal bone regenerative approaches in which a biodegradable porous structure providing mechanical stability and a hydrogel phase functioning as absorbing depot of endogenous proteins are simultaneously required. © 2016 Society of Chemical Industry