title: Effects of the surface characteristics of nano-crystalline and micro-particle calcium phosphate/chitosan composite films on the behavior of human mesenchymal stem cells in vitro.
abstract: Calcium phosphate (CaP) compounds, the main inorganic constituent of mammalian bone tissues, are believed to support bone precursor cell growth and osteogenic differentiation. Chitosan, a deacetylated derivative of chitin, is a versatile biopolymer to offer broad possibilities for cell-based tissue engineering. In the present study, different scales of CaP crystals on chitosan membranes were prepared for culture of human mesenchymal stem cells (hMSCs) in vitro. A series of aqueous CaP suspensions with different concentrations were mixed with chitosan solution and chitosan/calcium phosphate (C/CaP) films were fabricated by the solvent-casting method. With different weight ratios of CaP in chitosan solution, the various surface characteristics of nano-amorphous (C/CaP 0.1), nano-crystalline (C/CaP 0.5) and micro-particle (C/CaP 2) CaP compounds were examined by scanning electron microscopy and electron dispersion spectroscopy. X-ray diffraction on micro-particles of CaP indicated the formation of crystalline hydroxyapatite. The behavior of hMSCs, including proliferation, cell spreading and osteogenic differentiation, was studied on the C/CaP films. In basal culture medium, the incorporation of CaP into chitosan films could promote the proliferation of hMSCs. The C/CaP 0.5 film with connected CaP nano-crystals had better cellular viability. The fluorescence microscope images at 14 days of culture revealed extensive networks of F-actin filaments of hMSCs on chitosan, C/CaP 0.1 and C/CaP 0.5 films. The cellular morphology on C/CaP 2 film with discrete CaP micro-particles was partly restrained. In osteogenic medium, the alkaline phosphatase (ALP) activity of hMSCs increased and showed the process of osteogenic differentiation. The ALP levels on C/CaP 2 film were higher than those on C/CaP 0.1 and C/CaP 0.5 films. These results demonstrated that the crystallinity and topography of CaP on chitosan membranes could modulate the behaviors of cultured hMSCs in vitro.
authors.affiliation: a Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan 100, Republic of China; Department of Orthopedic Surgery, Min-Sheng General Hospital, Taoyuan, Taiwan 330, Republic of China; Department of Orthopedic Surgery, National Taiwan University Hospital, Taipei, Taiwan 100, Republic of China.
authors.forename: Y-T
authors.initials: YT
authors.lastname: Lee
authors.forename: B-Y
authors.initials: BY
authors.lastname: Yu
authors.forename: H-J
authors.initials: HJ
authors.lastname: Shao
authors.forename: C-H
authors.initials: CH
authors.lastname: Chang
authors.forename: Y-M
authors.initials: YM
authors.lastname: Sun
authors.forename: H-C
authors.initials: HC
authors.lastname: Liu
authors.forename: S-M
authors.initials: SM
authors.lastname: Hou
authors.forename: T-H
authors.initials: TH
authors.lastname: Young
mesh_terms: D000199:Actins / Q000378:metabolism; D002130:Calcium Phosphates / Q000737:chemistry; D049109:Cell Proliferation; D002470:Cell Survival; D002478:Cells, Cultured; D048271:Chitosan / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000502:physiology*; D049329:Nanostructures / Q000737:chemistry; D010012:Osteogenesis; D012996:Solutions; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties; D013535:Suspensions; D054457:Tissue Scaffolds / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D000199:Actins; D002130:Calcium Phosphates; D012996:Solutions; D012997:Solvents; D013535:Suspensions; D014867:Water; D048271:Chitosan; C020243:calcium phosphate