Preparation And Characterization Of Silk Fibroin As Carriers For Drug Delivery

As a natural, fibrous protein produced by a variety of insects and spiders, silk fibroin isfurther used for drug delivery with sustainable release properties. In particular, silk fibroinshave good biocompatibility and controllable degradability, demonstrating a preferredbiomedical material. Numerous studies have demonstrated that silk fibroin is an ideal drugcarrier. However, there are only few reports on targeted drug delivery and injectable silkhydrogel, which limited the application of silk fibroin.In this article, we explore the preparation of silk fibroin microspheres. Combinedwith magnetic Fe3O4nanoparticles, the silk fibroin can be prepared as SF-Fe3O4microspheres with magnetic targeting capability. As drug carrier, the microspherecan delivery drug to a specific position under external magnetic field and controlthe drug release behavior effectively, reducing the side effects of drugs to body andimproving the utilization of drugs. So it holds developing potential and applicationvalue. Silk fibroin solution was stirred slowly for long time to change the structureof molecular chains, so the injectable silk fibroin hydrogel was prepared under60℃.The silk fibroin microspheres were prepared by salted from potassium phosphate(pH=9). Fe3O4nanoparticles with size distribution were prepared by chemicalco-precipitation. Novel multifunctional iron oxide/silk-fibroin composite microspheresare fabricated via simple salting out process from potassium phosphate (pH=9). Thesemicrospheres are subsequently applied as drug delivery, specifical for loading doxorubicinhydrochloride.The results show that the drug loading capacity (LC) is3.3%and the drugencapsulation efficiency (EE) could reach up to76%. The DOX-loaded microspheresexhibit sustained and pH-sensitive release patterns. The total DOX release is measured tobe about60%at pH5.5. More interestingly, RhB-labelled Fe3O4–SF microspheres exhibit astriking endocytosis, selectively accumulating in the cytoplasm, which results in only~10%survival ratio of Hela cells after co-culture with DOX-Fe3O4-SF microspheres for48h. Theresults clearly indicate that Fe3O4–SF microspheres hold significant potential for targeteddrug delivery. Silk fibroin solution was stirred slowly for long time to change the structure ofmolecular chains, so the injectable silk fibroin hydrogel was prepared under60℃.The results show these low concentrations of silk fibroin hydrogels could flow. Thehydrogel was loaded DOX by adsorption and DOX/silk sibroin hydrogels exhibitsustained release patterns. The total DOX release is measured to be about65%at pH4.2.MTS results show there is only~20%survival ratio of Hela cells after co-culture withDOX/silk sibroin hydrogels. The results clearly indicate that the injectable silk sibroinhydrogel hold great applications.