A hydrogel dressing loaded with tea tree oil nanoemulsion accelerates methicillin-resistant Staphylococcus aureus-infected wound healing

Drug-resistant bacterial infections can easily lead to delayed wound healing and pose a serious threat to patients' health. Therefore, it was imperative to develop wound dressings to solve this problem. Herein, we developed a hydrogel based on laponite and polyacrylamide (PAAG/LAP) and loaded with tea tree oil nano-emulsion (nanoTTO) by a simple one-step mixing method via the principle of photopolymerization and its potential use and safety for MRSA-infected skin wounds. The evaluation showed that the PAAG/LAP/nanoTTO30% hydrogel exhibited excellent compressive resistance (∼85 kPa), good biocompatibility, and great antibacterial properties against MRSA in vitro and in vivo (over 90%). Cell migration results showed that the relative wound area ratio of the PAAG/LAP/nanoTTO30% hydrogel treatment group (~55.18%) was significantly lower than that of the control group (~68.89%). The results of the in vivo infection rat model showed that compared with other control groups, the PAAG/LAP/nanoTTO30% hydrogel treatment group had the lowest relative wound area ratio (8.78%) within 12 days. Moreover, the results showed the PAAG/LAP/nanoTTO30% hydrogel could promote MRSA-infected wound healing by directly killing bacteria and promoting angiogenesis. In conclusion, our study provided an antibacterial hydrogel dressing that does not require loading antibiotics for wounds infected by drug-resistant bacteria, expecting to achieve infected wound healing.