Nanoencapsulation of the Bioactive Acetyl Hexapeptide With Silk Fibroin for Potential Dermocosmetic Application

ABSTRACT The objective was to develop the encapsulation of acetyl hexapeptide (AHP) using silk fibroin nanoparticles (SFNP) as a polymer matrix, with potential application in topical dermocosmetic formulations. The SFNPs were characterized for morphology, size, structure, thermal properties, zeta potential, encapsulation efficiency, cell viability, active release, and in vitro cytotoxicity using L929 fibroblast cell lines. It was found that the amount of acetone used in dissolution influenced particle morphology and size, with the 90/10 ratio (solvent/SFNP) exhibiting a spherical shape, a rough surface, and greater size homogeneity. The encapsulation efficiency was 80.13%, and after the process, the particle diameter increased by 70 nm. However, the polydispersity index remained below 0.160 in both cases. The interaction between AHP and SFNP was enhanced in a slightly acidic medium due to surface charge interactions, with AHP displaying a positive charge and an electrophoretic mobility of 0.85 cm 2 /s·V. FTIR analysis confirmed the presence of AHP in the nanosystem. A release of 28% AHP was observed after 1440 min at pH 5.5, while at pH 7.4, the release increased to 43%. SFNP+AHP demonstrated no cytotoxicity at concentrations ranging from 0.10 to 0.15 μg/mL, with cell viability between 95% and 100%, indicating its suitability for application on epithelial tissue.