Low-frequency ultrasound increase effectiveness of silver nanoparticles in a purulent wound model

Bacterial biofilm formation and antibiotic resistance are the main factors of surgical wound complications. Traditional treatments in some cases cannot provide complete bacterial eradication and new therapeutic approaches should be developed to overcome antibiotic resistance. Silver nanoparticles (AgNPs) can be the first choice for bacteria treatment but their clinical application is limited due to toxic effects. Combination of AgNPs with the low-frequency ultrasound (US) treatment expected to decrease toxicity and leads to the facilitation of wound healing. In current research we investigated the antibacterial activity of AgNPs per se and in combination with low-frequency US, assessed the cytotoxicity of AgNPs on human dermal fibroblasts and finally, wound healing was evaluated in purulent wound model (96 white laboratory rats) applying AgNPs and US as a treatment strategy. Our results demonstrate no toxic effect of AgNPs in minimum inhibitory concentrations and show increasing their antibacterial effectiveness after US application. The combination of low-frequency US and AgNPs provides reduction of the inflammatory reaction, microorganism elimination and leads to facilitation of new tissue formation with complete epithelization. All effects were significant over the Chlorhexidine treatment, monotherapy with AgNPs or US. Advanced effectiveness of complex therapy opens new perspectives for clinical application of AgNPs solution accompanied by US.