| Silk fibroin was a natural protein produced by Bombyx mori. It exhibited a unique and useful combination of properties such as good biocompatibility, three-dimensional porous materials with excellent mechanical. These features provided early clues to the utility of regenerated silk fibroin as a scaffold/matrix biomaterial for tissue engineering. The silk fibroin scaffold used for tissue engineering should degrade in a rate to match the formation speed of a new tissue or organ. Therefore, two basic factors, conformation and pore size, were studied in this study to control the degradation behavior of silk fibroin scaffolds, with the methods of XRD, FTIR, SEM and so on. Here, the collagenase IA was used as the proteolytic enzyme to degrade Porous Bombyx mori Silk Fibroin Materials in vitro for simulating vivo condition. The present study was also conducted to investigate the behavior of the porous Bombyx mori silk fibroin in vivo (up to 55 days) in SD rats.The porous Bombyx mori silk fibroin materials with different conformation were prepared by controlling the freezing temperature and the treatment of EDC/NHS/MES or Alcohol. Through quantitative analysis in XRD and FTIR, the quantitative proportions of each conformation were obtained. Then each groups was degraded in vitro with collagenase IA for 18 days. The results showed that high content ofβ-sheet structure leaded to low degradation rate. The random coil region in the porous Bombyx mori silk fibroin materials degraded, while the crystal region kept stable and the crystallinity increased during incubation.The porous Bombyx mori silk fibroin materials with different pore size were prepared by controlling the concentration of silk fibroin solution and the freezing temperature. Through quantitative analysis in SEM and fluid-discharge therapy, the quantitative results of pore parameter were obtained. Then each groups was degraded in vitro with collagenase IA for 18 days. The results showed that big pore size and porosity leaded to fast degradation rate as the enzyme could easily contact the cleavage site, and the big density leaded to low degradation rate as the thickness effects of pore walls.In vivo degradation result showed that the form of cambium was closely similar with the normal structure after 55 days, and the porous Bombyx mori silk fibroin materials degraded approximately 96.37 %.These results demonstrated that through controlling the parameters such asβ-sheet structure content and pore size parameter, it is possible to control the biodegradation of the porous silk fibroin sheets. |
