Catechol cross-linked antimicrobial peptide hydrogels prevent multidrug-resistant Acinetobacter baumannii infection in burn wounds

Hospital-acquired infections are common in burn patients and are the major contributors of morbidity and mortality. Bacterial infections such as Staphylococcus aureus ( S. aureus ) and Acinetobacter baumannii ( A. baumannii ) are difficult to treat due to their biofilm formation and rapidly acquiring resistance to antibiotics. This work presents a newly developed hydrogel that has the potential for treating bacterial wound infections. The hydrogel formulation is based on an antimicrobial peptide (AMP), epsilon-poly-l-lysine (EPL) and catechol, which was cross-linked via mussel-inspired chemistry between the amine and phenol groups. In vitro studies showed that EPL-catechol hydrogels possess impressive antimicrobial and antibiofilm properties toward multidrug-resistant A. baumannii (MRAB). In addition, cytotoxicity study with the clonal mouse myoblast cell line (C2C12) revealed the good biocompatibility of this hydrogel. Furthermore, we created a second-degree burn wound on the mice dorsal skin surface followed by contamination with MRAB. Our results showed that the hydrogel significantly reduced the bacterial burden by more than four orders of magnitude in infected burn wounds. Additionally, there was no significant histological alteration with hydrogel application on mice skin. Based on these results, we concluded that EPL-catechol hydrogel is a promising future biomaterial to fight against multidrug-resistant bacterial infections.