title: [PREPARATION AND PERFORMANCE RESEARCH OF SILK FIBROIN COLLAGEN BLEND SCAFFOLD].
abstract: OBJECTIVE
  To prepare composite scaffold of different quality ratio of silk fibroin to collagen, analyze the scaffold performance, and optimize the quality ratio for chondrocyte tissue engineering.
  
  
  METHODS
  The silk fibroin/collagen composite scaffold was made using a freeze-drying technique in different quality ratios of silk fibroin to collagen: 4:2 (group A), 4:4 (group B), and 4:8 (group C). The porosity, water absorption expansion rate, mechanical properties, and pore size of composite scaffold were detected. The bone marrow mesenchymal stem cells (BMSCs) were isolated from 4-week-old male Wistar rats by density gradient centrifugation, and the third generation BMSCs were seeded onto the scaffolds at 2 x 10(7) cells/ mL density, and were cultured for 14 days. The cell proliferation was detected using MTT assay at 1, 3, 5, 7, 9, 11, and 13 days, the cell morphology and distribution were observed by HE staining and scanning electron microscopy (SEM).
  
  
  RESULTS
  The porosity of groups A, B, and C was 94.6% ± 1.6%, 80.6% ± 1.1%, and 60.6% ± 1.0% respectively; and significant differences were found between group A and groups B and C, and between group B and group C (P < 0.05). The water absorption expansion rates of groups A, B, and C were 1 523.7% ± 186.6%, 1 091.0% ± 151.6%, and 659.6% ± 161.4% respectively, showing no significant difference among 3 groups (F = 6.67, P = 0.08). The elasticity modulus of groups A, B, and C were (23.1 ± 2.5), (25.1 ± 2.3), and (29.8 ± 2.6) kPa respectively, showing no significant difference among 3 groups (F=2.00, P=0.28). The pore size of groups A, B, and C was (103 ± 12), (80 ± 15), and (60 ± 16) µm respectively, showing no significant difference among 3 groups (F = 2.22, P = 0.26). MTT results showed that the cell proliferation in the group A at 7, 9, 11, and 13 days were better than those in groups B and C (P < 0.05); at 14 days after cultivation, even pore size, good intercommunicating of holes, and good cells growth on the scaffolds with full extension and more extracellular matrix were seen under SEM in group A, but small pore size, poor intercommunicating of holes and poor cell growth on the scaffolds in groups B and C. HE staining and SEM results showed thatthe cells on the scaffold in group A was obviously more than those in groups B and C.
  
  
  CONCLUSIONS
  The scaffold prepared in a quality ratio 4 : of silk fibroin to collagen has better porosity, water absorption expansion rate, elasticity modulus, and pore size, on which the cells can grow well, so it is more suitable for cartilage tissue engineering.
authors.forename: Kai
authors.initials: K
authors.lastname: Sun
authors.forename: Zhenghao
authors.initials: Z
authors.lastname: Nian
authors.forename: Cheng
authors.initials: C
authors.lastname: Xu
authors.forename: Ruixin
authors.initials: R
authors.lastname: Li
authors.forename: Hui
authors.initials: H
authors.lastname: Li
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D002356:Cartilage; D018929:Cell Culture Techniques; D049109:Cell Proliferation; D019902:Chondrocytes; D003094:Collagen; D055119:Elastic Modulus; D005109:Extracellular Matrix / Q000737:chemistry* / Q000378:metabolism; D005349:Fibroins; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism; D016062:Porosity; D051381:Rats; D017208:Rats, Wistar; D047011:Silk; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D047011:Silk; D003094:Collagen; D005349:Fibroins