Bilayered electrospun membranes composed of poly(lactic-acid)/natural rubber: A strategy against curcumin photodegradation for wound dressing application

Curcumin is a natural phenolic compound renowned for its beneficial anti-carcinogenic, anti-oxidant, antibacterial and anti-inflammatory properties. More recently, this active compound has also demonstrated wound healing capability and antibacterial properties, which are essential prerequisites to treat skin injuries. However, the practical application of curcumin in wound-healing dressing is limited by its susceptibility to photodegradation when exposed to artificial or natural sunlight. To maintain the pharmacological and antibacterial properties of curcumin and prevent its photodegradation, we have developed a bilayered asymmetric membrane for wound healing application composed of two layers of electrospun fibers. The bottom layer is composed of a biodegradable blend of poly(lactic acid)(PLA)/natural rubber(NR) microfibers containing curcumin in the bulk. In contrast, the top layer is composed solely of PLA nanofibers to simultaneously protect curcumin against photodegradation and avoid bacterial penetration. Scanning electron microscopy, Fourier transform infrared spectroscopy, UV–Vis spectroscopy, thermal analyses, contact angle measurements and antibacterial assay were employed to investigate the properties of the membranes. Our results demonstrated the top layer of PLA was crucial to prevent the photodegradation of curcumin contained in the PLA/NR microfibers bottom layer and also avoided the penetration of bacteria for 10 days. Additionally, the PLA/NR microfibers showed strong antibacterial activity against Staphylococcus aureus. Our results demonstrated the potential of bilayered nano/microfibrous membranes to be applied in the design of wound dressings containing active compounds susceptible to photodegradation.