Enzymolysis and photothermal-mediated synergistic antimicrobial nanoplatform with programmed EPS degradation and biofilm penetration capabilities for eradication of biofilm wound infections

Abstract

It is an effective method of eradicating biofilm infection and promoting wound healing by exopolysaccharides (EPS) degradation and penetration of antimicrobial agents into biofilms. In this study, a synergistic antimicrobial nanoplatform (Pec@PLL-MoS2) based on programmed enzymolysis and photothermal therapy was developed. Pectinase (Pec) was modified onto the surface of molybdenum disulfide nanosheets (MoS2 NSs) by ε-poly-L-lysine (PLL) linkage via electrostatic adsorption. With the 808-nm laser irradiation, the activity of Pec was regulated by the photothermal effect produced by the MoS2 NSs. Pec efficiently degraded the EPS and destroyed the structural integrity of the biofilms, thus promoting the penetration of Pec@PLL-MoS2 into the biofilms. With the penetration of Pec@PLL-MoS2, the local hyperthermia produced by the photothermy of the MoS2 NSs further killed the bacteria inside the biofilms, eventually eradicating biofilm infections. In vitro experiments indicated that 81.1 % of Staphylococcus aureus (S. aureus) biofilms and 89.9 % of Escherichia coli (E. coli) biofilms were eradicated within 5 min. The survival rates of the bacteria in the biofilms of S. aureus and E. coli were reduced to 5.1 % and 0.1 %, respectively. In vivo, biofilm infections in wounds were completely eradicated by Pec@PLL-MoS2 under irradiation, thereby reducing inflammation and promoting wound healing. This study demonstrated that Pec@PLL-MoS2 based on programmed enzymolysis and photothermia is a new synergistic treatment strategy for biofilm infections.