Temperature-Responsive Antheraea pernyi Silk Fibroin/Poly(N-isopropylacrylamide) Hydrogels for Controlled Protein Drug Delivery

Temperature-responsive hydrogels provide hydrated matrices for regulating protein release near physiological temperature. Building on a previously developed p(ASF-AGE-NIPAAm) hydrogel platform, this study evaluated five formulations with ASF-AGE feed contents of 10.0–57.1 wt% as protein delivery carriers. The hydrogels exhibited lower critical solution temperatures (LCSTs) of 31.8–33.0 °C and reversible swelling–deswelling transitions during cyclic temperature switching between 20 and 40 °C. Increasing the ASF-AGE content decreased the equilibrium swelling ratio from 17.3 to 10.6 g/g, while the bovine serum albumin (BSA) encapsulation efficiency varied between 73.5% and 76.8% and the drug loading capacity decreased from 452.6 to 380.2 mg/g. BSA release was evaluated in phosphate-buffered saline (PBS, pH 7.4) and depended on both temperature and formulation: the apparent cumulative release at the end of the observation period ranged from 37.6% to 54.1% at 20 °C and from 38.4% to 61.2% at 37 °C. Release was higher at 37 °C, coinciding with thermally induced network contraction, and ASF-rich formulations generally released less BSA. These Results define a composition–property–release relationship for p(ASF-AGE-NIPAAm) hydrogels and show that the ASF content can be adjusted to balance protein loading against temperature-responsive release.