Antioxidative and Hypoglycemic Effects of Silk Fibroin/SericinMixtures in High Fat-Fed Mice

Design of Bombyx mori (B. mori) Silk Fibroin Microspheres for Developing Biosafe Sunscreen

Sunscreens play a crucial role in protecting the skin from ultraviolet (UV) damage. However, present commercial sunscreens have a tendency to generate free radicals in the UV window, resulting in serious inflammatory responses and health problems. In this study, we demonstrate that silk fibroin microspheres (SFMPs) assembled from regenerated silk fibroin (SF) could scavenge free radicals while preventing UV irradiation and thus present a promising sunscreen. The SFMP reflected more UV light than SF and presented a higher stability than that of organic commercial sunscreens. In vitro analysis proved that SFMP could more efficiently scavenge the hydroxy radical and reduce the intracellular reactive oxygen than titanium dioxide (TiO2). In vivo experiments exhibited that SFMP provided stronger skin protection against UV irradiation than commercial sunscreens and TiO2. Furthermore, SFMP treatment significantly inhibited the skin inflammatory response. This work suggests that the SFMP has great potential to be developed into a biosafe sunscreen.

Effect of degumming ratio on wet spinning and post drawing performance of regenerated silk

Regenerated silk fiber has attracted considerable attention because of its good blood compatibility and cytocompatibility, and the advantages of regenerated fiber, such as control of structure and properties. In this study, wet spun regenerated silk fibers were fabricated by controlling degumming ratio and silk concentration. Rheometry, X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy were used to examine wet spinning and post drawing performance of silk. Dope solution viscosity was found to be a key factor determining the continuous fiber formation of silk and 0.07Pa·s was essential for continuous fiber formation. Maximum draw ratio of the as-spun silk fiber was strongly affected by two factors: (1) crystallinity index from FTIR spectroscopy and (2) degumming ratio of silk. XRD of the wet spun silk fibers was not changed by the degumming ratio, silk concentration, and draw ratio. However, the crystallinity indices from FTIR were changed by these factors. Drawing-induced short-range crystallites of the silk were proposed based on FTIR and XRD. These results also show that XRD and FTIR can be used to characterize the micro-structure of silk complementarily because of their different detection characteristics: XRD and FTIR spectroscopy are sensitive to the detection of long- and short-range ordered crystallites of silk, respectively.