| Many reports indicated that silk fibroin of domestic silkworm Bombyx mori (B.mori SF) has good biocompatibilities and effect. However, the Antheraea pernyi(A.pernyi) silk fibroin not only has the advantage of B. mori SF in biological medicinefield, but also contains the tripeptide sequence Arg-Gly-Asp(RGD) which is known toexhibit specific interactions with mammal cells. Therefore, it is accepted to have betterbiocompatibility and effect than B.mori as a wound dressing, a scaffold for tissueengineering, a drug carrier and a cell culture substrate. On the base of researching in theproperties of regenerated A.pernyi silk fibroin solution (ASF), in this paper, we preparedthe A.pernyi silk fibroin microspheres for the first time and investigated the drug-releaseproperties of cancer drug adriamycin in vitro. At the same time, mixing the smallmolecular dihydric alcohol with A.pernyi silk fibroin molecules, A.pernyi silk fibroinblend porous materials and blend films which had excellent mechanical performanceand water-insoluble were prepared by this relatively mild method.Surface tension results showed that ASF had surface active and can significantlydecline the surface tension of water. And the regenerated ASF solution was sensitive andhighly unstable. So the microspheres were formed easily in ASF solution, and theaverage sizes of the silk particles greatly increased from3nm to1.5μm. In this process,the molecular conformation of regenerated ASF changed from α-helix to β-sheetstructure in solution. Then we prepared ASF microspheres, having a bettermonodispersity and regular shape, only through a simple way to adjust the pH value ofASF solution. Meanwhile, it is found that the ASF microspheres, with predictable andcontrollable sizes ranging from1to4μ m, can be prepared via changing the ASFsolution concentration. The merits of this novel method included a rather simpleproduction apparatus and no potentially toxic agents, such as cross-linking agent,initiators, surfactant, or organic reagent. The results showed that the shape of preparedmicrospheres were regular spherical structure when the pH value was about4.3(pI) in ASF solution, and the average size of microspheres was3.5μm when ASF concentrationwas10mg/mL. The mechanism of ASF microspheres formation was also discussed inthis paper: crystal nucleus formationâ†'multinuclear growthâ†'ageing.In order to develop biological material applied to the artificial skin, woundcoverage and so on, the ASF/BDO blend porous scaffold materials with the averagepore size of300～1000μm, the porosity of82%～92%and some mechanical propertywere prepared with freeze drying method. After ASF mixed with BDO, the polymerizedstructure of ASF was changed to β-sheet which make the solubility of the material bereduced to2%. Besides, compression property testing indicated that the compressivestress was improved obviously with increasing mass concentration of the silk fibroin.In addition, in this paper, dihydric alcohol (propylene glycol, ethanediol), no toxicside effect to human body, were mixed with ASF solution, then the ASF/propyleneglycol and ASF/ethanediol blend films were prepared by casting method. This methodmade silk fibroin film water-insoluble as well as improved its flexibility. The structureof ASF changed to β-sheet and the film became water-insoluble when the blend ratiowas at55:45. At the same time, the physiochemical performance of the blend films wasbest at this optimum blend ratio. In summary, the ASF/glycol blend film provided agreat potential as a biological material. |
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