Matriz polimérica biocompatível contendo nanopartículas de prata para aplicação como base em esmalte de unha

Abstract

Nitrocellulose has played a fundamental role in the development of nail polishes since the 1920s, establishing itself as a film-forming polymer. However, due to its high glass transition temperature, the use of resins and plasticizers became necessary to improve the flexibility and adhesion of the film. Since the 1940s, these additives have been associated with toxic and sensitizing effects, driving the search for safer and more sustainable alternatives, a challenge that remains in 2024. This study proposed the replacement of these additives with poly(ε-caprolactone) and polyethylene glycol, biocompatible and biodegradable polymers with plasticizing potential, whose combined application with nitrocellulose had not yet been explored. Poly(ε-caprolactone) was also investigated as a thermoplastic resin, given its ability to form films in association with nitrocellulose. Four experimental formulations of transparent nail polish bases (Bases 1A, 1B, 2A, and 2B), were developed and compared to a sample of pure nitrocellulose and to a commercial hypoallergenic base (Base C). The formulations were evaluated for water resistance, wettability, and cytotoxicity, showing comparable or superior performance to Base C, particularly in biocompatibility assays, where lower cytotoxicity indices were observed. The interaction and miscibility between the polymers were confirmed by dynamic mechanical analysis, which demonstrated a significant reduction in glass transition temperature, ranging from 30.5 °C to 40.0 °C, compared to pure nitrocellulose (107.5 °C) and Base C (34.0 °C), evidencing the plasticizing effect of poly(ε-caprolactone) and polyethylene glycol. Miscibility was also corroborated by X-ray diffraction, scanning electron microscopy, and refractive index analysis. Considering the therapeutic potential of nail polishes as delivery vehicles for active substances, silver nanoparticles were synthesized in situ in Bases 1B and 2B, selected based on the best results obtained in the preliminary assays. Nanoparticles formation was confirmed by the color change of the solutions, which acquired yellowish tones, and by the presence of characteristic absorption bands in the 444–448 nm region, detected by UV-Vis spectroscopy. Transmission electron microscopy revealed predominantly spherical nanoparticles with sizes ranging from 5 to 50 nm. The results demonstrate the potential of combining poly(ε-caprolactone) and polyethylene glycol as safe and effective alternatives to traditional plasticizers and resins in nail polish formulations, contributing to the development of less toxic products with improved functional properties and promising prospects for innovative therapeutic applications in the treatment of nail disorders.