title: Synthesis, characterization of chitosans and fabrication of sintered chitosan microsphere matrices for bone tissue engineering.
abstract: The objective of the present study was to synthesize and characterize chitosans with different degrees of deacetylation (DDA%), prepare chitosan microspheres with controlled chemistry and geometry, and fabricate three-dimensional (3-D) chitosan matrices based on microspheres with appropriate pore size, porosity and mechanical properties suitable for bone tissue engineering applications. Chitosans with three DDA% of 69%, 79% and 97% were obtained using a thermomechanochemical technique by varying the applied pressure and NaOH solution concentration. The prepared chitosans were comprehensively characterized by proton nuclear magnetic resonance, elemental analysis, viscosity measurements, thermal analyses and X-ray diffraction. In addition, chitosan microspheres were prepared using an ionotropic gelation method. Three-dimensional chitosan matrices were fabricated via a sintered microsphere technique. Scanning electron microscopy revealed rough surfaces of the prepared chitosan microspheres. Mercury intrusion porosimetry revealed a porosity of 19.2% and a median pore diameter of 199.62microm of the fabricated 3-D matrix. The compressive modulus of the sintered microsphere matrix (662.26+/-54.53MPa) was in the range of human cancellous bone (10-2000MPa), making it suitable for bone tissue engineering applications.
authors.affiliation: Department of Biomaterials, National Research Centre, Cairo, Egypt. nrcfifi@yahoo.com
authors.forename: Wafa I
authors.initials: WI
authors.lastname: Abdel-Fattah
authors.forename: Tao
authors.initials: T
authors.lastname: Jiang
authors.forename: Gehan El-Tabie
authors.initials: Gel-T
authors.lastname: El-Bassyouni
authors.forename: Cato T
authors.initials: CT
authors.lastname: Laurencin
mesh_terms: D001672:Biocompatible Materials / Q000378:metabolism*; D001842:Bone and Bones / Q000378:metabolism*; D048271:Chitosan / Q000138:chemical synthesis / Q000737:chemistry*; D019245:Compressive Strength; D004577:Electron Probe Microanalysis; D009682:Magnetic Resonance Spectroscopy; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D016062:Porosity; D012972:Sodium Hydroxide / Q000494:pharmacology; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry; D023822:Tissue Engineering / Q000379:methods*; D014783:Viscosity; D014961:X-Ray Diffraction
chemical_list: D001672:Biocompatible Materials; D012972:Sodium Hydroxide; D048271:Chitosan