Photo-cross-linkable hydrogels have recently gained increased interest in the field of biomedical applications. In this study, silk fibroin was derivatized with methacrylic anhydride (MA) to obtain silk fibroin methacryloyl (SFMA), forming hydrogel under UV light exposure in 1 min. The SFMA sol-gel transition did not involve significant structural change at the early stage. Then, the formation of the irreversible β-sheet was confirmed after 24 h. The resulting SFMA hydrogel showed a homogeneous porous structure with pore sizes ranging from 400 to 700 μm, depending on the content. In addition, these hydrogels demonstrated a lower swelling capacity, higher rheological properties and compressive modulus, and slow degradation behavior at higher content, likely due to the higher degree of cross-linking. An experiment with cells indicated the good cell compatibility of these hydrogels, as revealed by Cell Counting Kit-8 (CCK-8) assays. As a tissue-engineered material, this photo-cross-linkable SFMA is expected to have a wide range of applications in the biomedical field.

Introduction: Chronic osteomyelitis remains a clinical challenge in orthopedics.Methods: In this study, silk fibroin microspheres (SFMPs) loaded with vancomycin are entrapped in an injectable silk hydrogel to form a vancomycin delivery system for treatment of chronic osteomyelitis.Results and Discussion: Vancomycin showed continuous release from the hydrogel for up to 25 days. The hydrogel shows strong antibacterial activity against both Escherichia coli and Staphylococcus aureus and a long antibacterial duration of 10 days without a decrease in the antibacterial effect. The injection of vancomycin-loaded silk fibroin microspheres entrapped in the hydrogel into the infected site of rat tibia reduced bone infection and improved bone regeneration compared with other treatment groups.Conclusion: Thus, the composite SF hydrogel features a sustained-release profile and good biocompatibility, making it promising for application in osteomyelitis treatment.

The possibility of using nonmulberry silk fibroin as a biomaterial is a subject of broad interest due to its inherent RGD sequence. However, the extraction of silk fibroin from cocoons and silk glands remains a formidable task. In this work, we report a facile method to dissolve tussah silk using CaCl₂–formic acid and a water-rinsing process for regeneration of tussah silk fibroin (TSF) film. The new technique is important and valuable because it can directly extract silk fibroin from cocoons and is advantageous over other previous reported methods using LiSCN and Ca(NO₃)₂. The morphology, chemical structure, and mechanical properties of regenerated film rinsed with water, ethanol, and methanol are characterized by scanning electron microscopy, Fourier transform infrared, and X-ray diffraction techniques in combination with mechanical testing. The results reveal that the regenerated TSF films possess a smooth surface and nanostructural cross section and exhibit predominantly β-sheet crystal structure and good mechanical properties in wet state. In addition, enhanced cell attachment and proliferation of bone marrow stem cells are observed on water-rinsed TSF film. The present study provides a novel way for dissolution and regeneration of tussah silk, and the resulting TSF films are a promising biomaterial for tissue engineering applications.