Chitosan membrane tailored for topical acne treatment by incorporating Pickering encapsulated tea tree oil based on organosilane-modified palygorskite.

This study reports a facial approach to fabricate hydrogel membranes with tailored application in topical acne therapy by incorporating tea tree oil (TTO)-loaded Pickering emulsion stabilized by dodecyl triethoxysilane-modified palygorskite in chitosan (CS)/hydroxyethyl cellulose (HEC) polymer matrix. This adding Pickering encapsulated TTO strategy endowed the CS/HEC membrane with increased membrane thickness, mechanical strength, surface hydrophilicity and body fluid absorbability as well as a decreased transparency, all of which could be tailored by adjusting the content of TTO Pickering emulsion in the polymer matrix during preparation. Compared with the TTO directly added membrane, the composite membranes possessed well-distributed small droplets of TTO in the continuous phase of membrane matrix, which can be slowly released at skin physicochemical conditions within 10 h, providing favorable antioxidant scavenging of DPPH and potent bacterial inhibitory effects against Propionibacterium acnes and Staphylococcus aureus. Moreover, the Pickering TTO/CS/HEC membranes exhibited advanced efficacy over the plain CS/HEC membrane in clearing facial acnes by reducing the size of flamed acnes and restoring the impaired barrier function. These findings have broadened the applicability of chitosan-based polymeric membranes in the dermocosmetic field by incorporating Pickering encapsulated essential oils and provide insights into the development of novel multifunctional wound dressings.