title: Novel silk fibroin films prepared by formic acid/hydroxyapatite dissolution method.
abstract: Bombyx mori silk fibroin from the silkworm was firstly found to be soluble in formic acid/hydroxyapatite system. The rheological behavior of silk fibroin solution was significantly influenced by HAp contents in dissolved solution. At the same time, silk fibroin nanofibers were observed in dissolved solution with 103.6±20.4nm in diameter. Moreover, the structure behavior of SF films prepared by formic acid/hydroxyapatite dissolution method was examined. The secondary structure of silk fibroin films was attributed to silk II structure (β-sheet), indicating that the hydroxyapatite contents in dissolved solution were not significantly affected by the structure of silk fibroin. The X-ray diffraction results exhibited obviously hydroxyapatite crystalline nature existing in silk fibroin films; however, when the hydroxyapatite content was 5.0wt.% in dissolved solution, some hydroxyapatite crystals were converted to calcium hydrogen phosphate dehydrate in silk fibroin dissolution process. This result was also confirmed by Fourier transform infrared analysis and DSC measurement. In addition, silk fibroin films prepared by this dissolution method had higher breaking strength and extension at break. Based on these analyses, an understanding of novel SF dissolution method may provide an additional tool for designing and synthesizing advanced materials with more complex structures, which should be helpful in different fields, including biomaterial applications.
authors.affiliation: National Engineering Laboratory for Modern Silk, Soochow University, Suzhou 215123, China; College of Textile and Clothing Engineering, Soochow University, Suzhou 215021, China. Electronic address: jinfa.ming@gmail.com.
authors.forename: Jinfa
authors.initials: J
authors.lastname: Ming
authors.affiliation: National Engineering Laboratory for Modern Silk, Soochow University, Suzhou 215123, China; College of Textile and Clothing Engineering, Soochow University, Suzhou 215021, China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Liu
authors.affiliation: National Engineering Laboratory for Modern Silk, Soochow University, Suzhou 215123, China; College of Textile and Clothing Engineering, Soochow University, Suzhou 215021, China.
authors.forename: Shiyu
authors.initials: S
authors.lastname: Bie
authors.affiliation: Jiangsu Province Key Laboratory of Stem Cell Research, Medical College, Soochow University, Suzhou 215006, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Zhang
authors.affiliation: National Engineering Laboratory for Modern Silk, Soochow University, Suzhou 215123, China; College of Textile and Clothing Engineering, Soochow University, Suzhou 215021, China. Electronic address: bqzuo@suda.edu.cn.
authors.forename: Baoqi
authors.initials: B
authors.lastname: Zuo
mesh_terms: D000818:Animals; D012831:Bombyx / Q000737:chemistry / Q000378:metabolism; D017886:Durapatite / Q000737:chemistry*; D005349:Fibroins / Q000737:chemistry*; D005561:Formates / Q000737:chemistry*; D057139:Nanofibers / Q000737:chemistry; D012995:Solubility
chemical_list: D005561:Formates; C030544:formic acid; D005349:Fibroins; D017886:Durapatite
keywords: Film; Hydroxyapatite; Mechanical property; Silk fibroin