Nanocápsulas poliméricas de óleo essencial de breu branco: síntese e caracterização por nanoprecipitação e microfluídica

Abstract

In the biomedical field, white breu essential oil stands out due to its therapeutic properties, such as anti-inflammatory, antimicrobial, and antioxidant effects. However, its volatility and difficulty of extraction limit its application, making nanotechnology a promising strategy for encapsulation and use in therapeutic systems. This study aimed to develop and characterize polymeric nanocapsules containing white breu essential oil using nanoprecipitation (NP) and microfluidics (MF). Both approaches were evaluated for their efficiency in producing nanocapsules, focusing on investigating the stability and cellular viability of the encapsulated essential oil. The nanoprecipitation technique produced nanocapsules using polycaprolactone (PCL) as the encapsulating matrix. A Box-Behnken experimental design with three factors and three levels was employed to optimize the production conditions, considering parameters such as the concentrations of PCL, essential oil, and surfactant. Subsequently, the optimized nanoprecipitation conditions were adapted to a microfluidic system, in which the aqueous and organic phases were simultaneously injected into a chip with a fishbone geometry. The nanocapsules were characterized by dynamic light scattering (DLS), thermal stability studies (performed by storage at different times and temperatures), cellular viability assay (MTS), and cell migration in keratinocytes. The NP-derived nanocapsules exhibited an average hydrodynamic size of 172.07 nm ± 2.9, a polydispersity index of 0.14 ± 0.04, and a Zeta potential (ζ) of –25.49 ± 1.08 mV, while the MF-derived nanocapsules measured 191.25 nm ± 4.51, with a PDI of 0.2 ± 0.1 and a ζ of –20.56 mV ± 0.48. The microfluidics-produced nanocapsules demonstrated greater physical stability and cellular viability in keratinocytes—exceeding 80% at a 1:2 dilution—whereas the nanoprecipitation-derived nanocapsules achieved >80% viability at a 1:8 dilution. In the cell migration assay, cells treated with the nanocapsules showed wound closure (scratch) comparable to the positive control (31.78 ± 5.39%), suggesting that the nanocapsules create an environment conducive to cell growth. Consequently, both techniques yielded stable, biocompatible nanocapsules that are potentially useful for biomedical applications, emerging as a promising alternative for the sustained release of bioactive compounds from the Amazon.