Obtaining PCL/tea tree oil particles with antimicrobial capacity and high cytocompatibility

Essential oils are a vast class of compounds that have many interesting therapeutical properties. In this sense, tea tree oil (TTO) stands out for its antioxidant, antifungal, antibacterial, anti-inflammatory, and antihyperproliferative potential. However, the low stability and solubility of these compounds can limit their therapeutical capacity, making it necessary to adopt a strategy to overcome this mishap. In that regard, nanoencapsulation can be highlighted as a promising maneuver capable of protecting the active and increasing its solubility in water, promoting greater compatibility and bioavailability. Based on the above, the main objective of this study was to evaluate polycaprolactone/Pluronic F-127 PCL/F-127 polymeric nanoparticles loaded with 10–30% w/w TTO obtained via nanoprecipitation. The obtained particles were evaluated by atomic force microscopy and UV–Vis spectroscopy to determine retention efficiency and obtain the release profile (with the evaluation of release models), time-domain nuclear magnetic resonance, antimicrobial activity, and cytotoxicity in fibroblasts and epithelial cells. The obtained results show the formation of particles of spherical-type morphology particles with smooth surfaces and particle sizes around 400 nm, with retention efficiencies between 60 and 70% and sustained release profile for up to about 6 or 7 h and compatible with the Higuchi model. Regarding the antimicrobial activity of the systems, it was observed that TTO presents antimicrobial activity against the evaluated strains (S. aureus, C.albicans, and E.coli) and that the encapsulation process can increase the activity against the strain of E. coli. Finally, the cytocompatibility analyses showed that the NNPs obtained are not cytotoxic to the cell lines evaluated.