title: Tissue engineered bone formation using chitosan/tricalcium phosphate sponges.
abstract: BACKGROUND
  Chitosan is a biodegradable natural polymer that has been shown to improve wound healing. This study aimed to develop chitosan/tricalcium phosphate (TCP) sponges as tissue engineering scaffolds for bone formation by three-dimensional osteoblast culture.
  
  
  METHODS
  The sponges were prepared by freeze-drying and cross-linking a mixture of chitosan solution with TCP. Fetal rat calvarial osteoblastic cells were isolated, cultured, and seeded into the sponges. The cell-sponge constructs were cultured for 56 days. Cell proliferation, alkaline phosphatase (ALPase) activity, and calcium deposition in the cell-sponge constructs were measured at 1, 7, 14, 28, and 56 days. Histologic examination was performed with light microscopy and scanning electron microscopy.
  
  
  RESULTS
  Chitosan/TCP sponges supported the proliferation of osteoblastic cells as well as their differentiation as indicated by high ALPase activities and deposition of mineralized matrices by the cells. Light and scanning electron microscopic examination indicated that seeded osteoblastic cells were well attached to sponge matrices and proliferated in a multi-layer fashion. Small bone-like spicules were observed on the sponge matrix at 14 days. Seeded cells appeared to be embedded in the newly formed tissue matrix, which is characteristic of the osteoblast differentiation and their progression into osteocytic cells. The amount of mineralized tissue formed in the sponge at 56 days was significant.
  
  
  CONCLUSIONS
  These results suggest that the chitosan/TCP sponge is a feasible tool as a scaffolding material to grow osteoblast in a three-dimensional structure for transplantation into a site for bone regeneration.
authors.affiliation: Department of Periodontology, College of Dentistry, Seoul National University, Korea.
authors.forename: Y M
authors.initials: YM
authors.lastname: Lee
authors.forename: Y J
authors.initials: YJ
authors.lastname: Park
authors.forename: S J
authors.initials: SJ
authors.lastname: Lee
authors.forename: Y
authors.initials: Y
authors.lastname: Ku
authors.forename: S B
authors.initials: SB
authors.lastname: Han
authors.forename: S M
authors.initials: SM
authors.lastname: Choi
authors.forename: P R
authors.initials: PR
authors.lastname: Klokkevold
authors.forename: C P
authors.initials: CP
authors.lastname: Chung
mesh_terms: D020341:Absorbable Implants; D000469:Alkaline Phosphatase / Q000032:analysis; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D001698:Biomedical Engineering; D001704:Biopolymers / Q000737:chemistry*; D018786:Bone Substitutes / Q000737:chemistry*; D002113:Calcification, Physiologic; D002118:Calcium / Q000032:analysis; D002130:Calcium Phosphates / Q000737:chemistry*; D002448:Cell Adhesion; D002454:Cell Differentiation; D002455:Cell Division; D002478:Cells, Cultured; D002686:Chitin / Q000031:analogs & derivatives* / Q000737:chemistry; D048271:Chitosan; D003432:Cross-Linking Reagents / Q000737:chemistry; D005240:Feasibility Studies; D005612:Freeze Drying; D008855:Microscopy, Electron, Scanning; D010006:Osteoblasts / Q000502:physiology; D010011:Osteocytes / Q000502:physiology; D010012:Osteogenesis / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D001672:Biocompatible Materials; D001704:Biopolymers; D018786:Bone Substitutes; D002130:Calcium Phosphates; D003432:Cross-Linking Reagents; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; D002686:Chitin; C485838:calcium phosphate, monobasic, anhydrous; D048271:Chitosan; C020243:calcium phosphate; D000469:Alkaline Phosphatase; C485829:calcium phosphate, dibasic, anhydrous; D002118:Calcium