Narrow Results

Aqueous silk fibroin (SF) sol is a colloidal solution. With the colloidal hydration layer and electrostatic repulsion, the SF sol can hardly make the efficient collision/assembly among micelles and perform like a following sol for a long time. In this paper, hydrophilic silk-based sequences (HSF) derived from SF molecules were obtained by immersing the dried SF condensates with water and extracting the dissolving fraction. The HSF was obtained by immersing the SF condensate dried at the temperature of $20$–$25^{\circ }\mathrm{\text{C}}$ and relative humid of 55–60% in water and collected the lixivium. The dissolving ratio was about 30%. The HSF sol (0.5%, w/v) self-assembled into the mesoscopic 3D nanofibrous network within 8 h. The obtained HSF nanofibers were 10–100 $\mu \mathrm{\text{m}}$ in length and 50–100 nm in diameter. The HSF nanofiber possesses similar hierarchical structure consisting of nanofibrils bundles to the native silk fiber. There were significant aggregation structure transitions from random coil to $\beta$-sheet and amorphous chains to Silk II crystal aggregation during the formation of HSF nanofibers. The HSF nanofiber holds the potential to give further insight into the reconstruction of native silk in vitro and the fabrication of tough silk-based biomaterials.

Blending with another biocompatible natural polymer is a potential way to enhance the mechanical properties and cell affinity of chitosan gels. In this study, chitosan (CH)/silk fibroin (SF) hybrid gels were fabricated by initiating gelation using β-glycerol phosphate at 37°C. Statistical analysis results from SEM images showed that the internal pore diameter of CH/SF gels with blending ratio of 75/25 was about 93.9 μm, and a number of micro fibers with the size of several micrometers were observed within the gels. Mechanical measurements showed that the compressive strength of CH/SF gels with blending ratio of 75/25 was about 4.39 kPa which were significantly bigger than that of CH gels, and it showed viscoelasticity characteristics of the elastic materials by rheological tests. Bone marrow mesenchymal stem cells were incubated on CH/SF blend gels for 3 days. Results from SEM and LSCM observation showed that blending CH with SF was beneficial for the cell attachment, spreading and proliferation. These results indicated that the CH/SF gel is expected to be useful in tissue engineering.

In this work, the oxidized bacterial cellulose (BC) was modified by silk fibroin (SF) to improve its blood compatibility. The oxidized BC pellicles were added to the aqueous silk fibroin solution containing crosslinking agents at room temperature for different times to obtain the composite membranes. The structure of the new composites membranes were evaluated by X-ray photoelectron spectroscopy (XPS). The results showed that silk fibroins were successfully fabricated on the oxidized bacterial cellulose (OBC) membranes surfaces, and the analysis on the quantity of the elements exhibits that the atom percentage of nitrogen reaches its maximum value at 24 h. The platelet adhesion, hemolytic test and protein adsorption results exhibited that the OBC/SF had significantly excellent blood compatibility featured by lower platelet adhesion and protein adsorption without causing hemolysis. This work provides a simple approach to fabricate composite biomaterials which exhibit wide biomedical application prospects.