Combination of Chlorhexidine and Silver Nanoparticles: an Efficient Wound Infection and Healing Control System

Purulent wounds are associated with microbial persistence that alters healing and can lead to septic complications. Infected wound management includes use of antibacterial agents for providing fast and complete bacterial elimination with no adverse effects on tissue repair. The performance of chlorhexidine (Ch) irrigation as the main strategy for purulent wound treatment is still under debates and stimulates further development of antimicrobial strategies. In this study, the effects of silver nanoparticles (AgNP) on infected wound microbiology and healing were assessed in vitro and in vivo. AgNPs provided high antibacterial activity at the minimal inhibitory concentration (MIC) of 1.25 μg/mL for E. coli and P. aeruginosa, and 2.5 μg/mL for S. aureus. At the same time assessment of AgNPs, cytotoxicity in fibroblast culture demonstrated high cytocompatibility in concentrations 5 times higher than MIC. These data agreed with in vivo studies with purulent wound modeling followed by use of three treatment options: Ch-, AgNP, and Ch+AgNP wound dressings. It was shown that AgNP treatment effectively decreased the microbial contamination but had only slight effect on wound healing parameters. In contrast, Ch+AgNP combination was associated with significant acceleration of wound clearance and closure related with early M2 macrophage polarization and an enhanced healing process. In conclusion, adding of AgNPs to chlorhexidine treatment improves infected wound healing through acceleration of bacteria elimination and M2 macrophage polarization. Synergic effects of AgNPs and chlorhexidine could be a promising option for optimizing infected wound management.