Preparation And Research On Regenerated Tussah Silk Fibroin Applied To Electrospun Nanofibers

Regenerated tussah silk fibroin(TSF) nanofiber mats were prepared by electrospinning, then the relationship between process parameters and its structure as well as its properties were analysed theoretically. On the basis of this analysis, TSF/PLA blend nanofiber mats were prepared, and its structure and property were tested and analysed, which provide evidence for tussah silk fibroin and PLA blended fiber mats for tissue engineering materials.The differences of structure and properties between tussah silk fibroin and silk fibroin were studied in this paper. The results showed that the degree of crystallinity was lower in tussah silk fibroin, while its grain was more perfect and its Grain Size was larger than the corresponding plane of silk fibroin. C C-peptide chain was the characteristic absorption peak of TSF due to its more Alanine (Ala). The sequence of TSF, by comparison, contained not only several basic amino acids but also the tripeptide sequence Arg- Gly- Asp (RGD), therefore, TSF nanofiber mats could display a high cell adhesion, which made it a promising material for a number of biomedical and biotechnological applications.Then, the pure TSF nanofiber mats were prepared with the solvent of Hexafluoro-2-propanol (HFIP). Furthermore, the effects of spinning voltage and spinning distance as well as ethanol treatment on the morphology and structure of the blend mats were also discussed. From all the experimental results in this paper, the optimal process parameters could be obtained as following: solvent weight concentration of HFIP solution 8%, applied voltage 12kv, spinning speed 0.3mL/h and electrode distance 10cm. The fiber diameter under this condition was 245nm in average, which decreased first with its voltage then increased, and increased with its spinning distance firest then dreased. But the results showed that the changes of parameters had little effect on fiber morphology and structure. While the content ofβ-sheet conformation was significantly increased after ethanol treatment, and the silk fiber conformation transited from silk I to silk II.TSF/PLA blend fiber mats were electrospun and compared the difference of the appearance with the blend mats through scanning electron microscopy (SEM) pictures. The experimental results showed that TSF/PLA fibers had regular spherical surface and the blend fiber diameter decreased obviously. PLA did effect on conformation which the content ofβ-sheet in TSF/PLA blend mats was more than that in pure TSF nanofiber mats by X-ray diffraction and IR spectra test. Through the analysis of TG curve, we had confirmed that compared with pure TSF nanofiber mats, the blend mats had good thermal stability, and its breaking strength increased with the increasing content of PLA as well. When 10% content of PLA added, the breaking strength of the blend mats reached 2.727 N/mm~2; due to nanofibers' high specific surface areas, 10% content of PLA would induce conformation to transfer from silk I to silk II.