Electrospun anti-inflammatory patch loaded with essential oils for wound healing

Wound healing is a complex process that consists of three overlapping phases: inflammation, proliferation, and remodeling. A bacterial infection can increase inflammation and delay this process. Microorganisms are closely related to the innate immune system, such as macrophages and neutrophils, as they can start an inflammatory cascade. Essential oils play an important role in the inhibition and prevention of bacterial growth due to their ability to reduce antimicrobial resistance. The possibility to find a strategy that combines antimicrobial and antiinflammatory properties is particularly appealing for wound healing. In this work, we showcase a variety of patches based on electrospun polycaprolactone (PCL) nanofibers loaded with natural compounds derived from essential oils, such as thymol (THY) and tyrosol (TYR), to achieve reduced inflammation. In addition, we compared the effect these essential oils have on activated macrophages when incorporated into the PCL patch. Specifically, we demonstrate that PCL-THY resulted in more efficient down-regulation of pro-inflammatory genes related to the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappa b) pathway when compared to PCL-TYR and the combination patch containing TYR and THY (i.e., PCL-TYR-THY). Furthermore, PCL-THY displayed low affinity for cell attachment, which may hinder wound adherence and integration. Overall, our results indicate that THY-loaded patches could serve as promising candidates for the fabrication of dressings that incorporate bactericidal and anti-inflammatory properties while simultaneously avoiding the limitations of traditional antibiotic-loaded devices.