Solution blow spun keratin - PVP nanofibers as a green platform for high-efficiency curcumin encapsulation and controlled release.

Despite its wide range of beneficial pharmacological effects, curcumin (Cur) has limited clinical applicability due to its extremely low water solubility. In this study, a novel curcumin-loaded nanofiber system was fabricated by combining polyvinylpyrrolidone (PVP) and keratin (Ker) using the solution blowing spinning (SBS) method. The nanofibers (Cur-loaded PxKyF) were produced using water as the solvent, without the use of any crosslinking agents. The incorporation of keratin resulted in thinner (∼ 349 nm) and more uniform nanofibers, with enhanced elongation at break and toughness. Among the formulations studied, the composite nanofiber with a PVP-to-keratin mass ratio of 1:1 (P1K1F) exhibited the most favorable properties as a curcumin delivery system. Notably, Cur-loaded P1K1F increased the aqueous solubility of curcumin by approximately 950-fold and enabled a controlled release profile. Interactions between Cur and P1K1F were investigated using FT-IR, UV-Vis spectroscopy, XRD, DSC, and PLM, confirming the successful formation of an amorphous complex. The release behavior of curcumin was further evaluated under varying pH and temperature conditions. Compared with PVP-only nanofibers, the incorporation of keratin significantly enhanced the practical performance of curcumin: permeation increased by approximately four-fold, while cell viability improved by nearly ten-fold at 1000 µg/mL, demonstrating improved biocompatibility. These results demonstrate that PxKyF nanofibers are a promising platform for curcumin delivery, with significant potential for transdermal applications in cosmetic formulations.