Effect of CeO2 NPs on stability of regenerated silk fibroin against UV-aging

Regenerated silk fibroin (RSF) fibers have great application prospects in medicine, textiles, optoelectronics, and other fields. However, under the synergistic action of ultraviolet, oxygen, and water, RSF will inevitably become brittle, which will greatly shorten the service life of RSF. Therefore, it is urgent to find some methods to protect RSF from aging damage. Cerium dioxide nanoparticles have a strong ultraviolet absorption and antioxidant capacity and have been used as an anti-aging component for other biomaterials. Thus, the RSF/CeO 2 NPs hybrid fibers were successfully prepared, and a series of artificial aging tests were carried out. Mechanical property is an important index to measure the aging degree. After aging, compared with RSF, the stress of RSF/CeO 2 NPs hybrid fibers was increased by 130.47 ± 4.78 MPa, and the strain of RSF/CeO 2 NPs hybrid fibers was increased by 69.89% ± 1.37%. The results of Fourier transform infrared spectroscopy, UV–Vis, sodium dodecyl sulfate polyacrylamide gel electrophoresis discussed the protective mechanism of CeO 2 NPs, which prevent the transition from β-sheet to α-helix/random coil and the disorder of structure. Furthermore, RSF/CeO 2 NPs hybrid fibers have an excellent antibacterial activity against Escherichia coli and Staphylococcus aureus bacteria; the antioxidant activity of RSF/CeO 2 NPs hybrid fibers is gradually enhanced in the presence of UV-light.