Sprayed Pickering emulsion with high antibacterial activity for wound healing

Effective treatment of wound injuries can prevent infections and promote healing. In this work, a sprayed Pickering emulsion composed of chitosan nanoparticles, tea tree oil and curcumin was formulated. The shear thinning behaviour allowed this Pickering emulsion to spray even with a high viscosity provided by the aqueous phase containing chitosan nanoparticles. Moreover, the Pickering emulsion could recover to the high viscosity after spraying onto the wounds, leading to the long residence time and intimate contact. In addition, the Pickering emulsion provided a carrier to encapsulate the tea tree oil, which caused sustained-release effects and further strengthened tea tree oil's antibacterial activity towards the Gram-negative Escherichia coli (E. coli), Gram-positive Staphylococcus aureus (S. aureus) and Gram-positive methicillin-resistant Staphylococcus aureus (MRSA). Besides, this multi-phase system offered a platform to load with hydrophobic curcumin, leading to better synergistic healing effects. Meanwhile, the Pickering emulsion avoided the irritation and toxicity related to surfactants, which was far safer than the classical emulsion especially when used in the defective skin. All these excellent properties endowed this sprayed Pickering emulsion with promising prospects for wound healing.