Poly(lactic acid)/poly(arginine) nanoparticles loaded with resveratrol: antioxidant potential and biocompatibility

Resveratrol is a polyphenol with potent antioxidant activity; however, its application in topical formulations is limited by low aqueous solubility and poor stability. Polymeric nanoparticles represent an attractive strategy to overcome these limitations. Poly(D,L-lactic acid) (PLA) nanoparticles coated with poly(arginine) were prepared by nanoprecipitation and loaded with resveratrol at 5%, 10%, and 15% (w/w). The systems were characterized in terms of particle size, morphology, zeta potential, encapsulation efficiency, antioxidant activity, thermal stability, chemical structure, and cytocompatibility using L929 fibroblasts and HaCaT keratinocytes. The nanoparticles exhibited spherical morphology and mean diameters in the range of 100-150 nm, with high colloidal stability maintained for up to six months. Encapsulation efficiency decreased with increasing drug loading, from 84% at 5% to 62% at 15%. FTIR analysis indicated physical incorporation of poly(arginine) and resveratrol without detectable chemical interactions, while TGA confirmed adequate thermal stability of the systems. Antioxidant activity ranged within similar levels for free and encapsulated resveratrol, with no statistically significant differences among formulations in the DPPH assay. All formulations demonstrated excellent cytocompatibility, with cell viabilities exceeding 95%. Poly(arginine)-coated PLA nanoparticles constitute an effective platform to enhance the physicochemical stability of resveratrol while maintaining its antioxidant activity and biocompatibility. Among the evaluated systems, the 5% and 10% formulations exhibited the most balanced overall performance.