title: Regenerated silk fibroin films with controllable nanostructure size and secondary structure for drug delivery.
abstract: The ability of drug release from SF materials was governed largely by their secondary structure. It is known that the breakage degree of the peptide chain during the silk fibroin (SF) dissolution can affect the structure, property, and applications of SF materials. To deeply understand this effect, we designed a reaction system based on CaCl2/H2O/C2H5OH ternary solvent with different ethanol content to obtain the regenerated SF films with different morphologies and secondary structures. The results showed that the globule-like nanostructure was observed in all regenerated SF films, and their size decreased significantly with reducing the ethanol content in the solvent. Correspondingly, the β-sheet structure content of the SF films increased. In addition, the contact angle and the elongation ratio increased, and water absorption decreased significantly with decreasing the ethanol content in the solvent. The accumulated release percents of doxorubicin from these SF films were significantly different with increasing the time. With smaller nanostructure size and more β-sheet content, the SF films had a slower drug release at the beginning. This study indicated the importance of the ethanol content in the solvent in controlling the structure and properties of the regenerated SF films, which would improve the application of SF in drug delivery.
authors.affiliation: National Engineering Research Center for Nanotechnology, Shanghai 200241, People's Republic of China.
authors.forename: Juan
authors.initials: J
authors.lastname: Zhou
authors.forename: Bin
authors.initials: B
authors.lastname: Zhang
authors.forename: Lijun
authors.initials: L
authors.lastname: Shi
authors.forename: Jian
authors.initials: J
authors.lastname: Zhong
authors.forename: Jun
authors.initials: J
authors.lastname: Zhu
authors.forename: Juan
authors.initials: J
authors.lastname: Yan
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.forename: Chuanbao
authors.initials: C
authors.lastname: Cao
authors.forename: Dannong
authors.initials: D
authors.lastname: He
mesh_terms: D002152:Calorimetry, Differential Scanning; D004337:Drug Carriers; D005349:Fibroins / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D049329:Nanostructures; D010316:Particle Size; D011487:Protein Conformation; D047011:Silk / Q000737:chemistry*; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry; D014961:X-Ray Diffraction
chemical_list: D004337:Drug Carriers; D047011:Silk; D005349:Fibroins
keywords: drug release; nanostructure size; secondary structure; silk fibroin; solvent