Preparation And Characterization Of β-tricalcium Phosphate Scaffolds With Controlled Porous Architecture By The In-situ Consolidation Method

Ideal tissue engineering scaffolds were based upon human bone tissues whichown excellent interconnectivity pore geometry and certain mechanical strength. Idealtissue engineering scaffolds were based upon human bone tissues which ownexcellent interconnectivity and critical pore geometry,while the tranditional methodsof preparing tissue engineering scaffolds were still far from satisfactory.RapidPrototyping has higher precision which can fabricate parts with complex shapes andcontrol structure of scaffolds.However this method could be only applied to somebio-inactive polymers. In this study, Rapid Prototyping, the same as In-situconsolidation method, was adopted to prepare β-tricalcium phosphate scaffolds(β-TCP) with controlled porous architecture.The objective of this work was to investigate and optimize a preparation processwhich could prepare three-dimensional porous inorganic scaffolds with controlledpore structure for industrial production. The results of the rheology of suspension ofβ-TCP powder indicated that the β-TCP slurry with solid volume loading50%(V/V),adding1wt%sodium polyacrylate as dispersant and1.5wt%modified starch ascoagulant, had ideal viscosity and was suitable for need of gelcasting technology. Theβ-tricalcium phosphate slurry with high solid content was poured into the polymerporous moulds with different pore structure, which were fabricated by rapidprototyping technique, then the β-tricalcium phosphate three-dimensional porousscaffolds were obtained by in situ consolidation of gel-casting. The pore structure ofscaffolds was characterized by micro-computed tomography (micro-CT), and thephase composition, morphology images and compressive strength of the porousscaffolds were tested. The scaffolds using polymer porous models have connectivemacro-pores structures. The compressive strength and macro-pores porosity ofscaffolds were more than2MPa and more than50%.The average compressivestrength and porosity of scaffold with regular pore (macro-pores of about800m)using polymer porous models B were2.21±0.36MPa and53.2%. The results indicate this method is an effective way to control the pore structure and pore size ofβ-tricalcium phosphate tissue engineering scaffold with full interconnectivity.Chitosan, gelatin solutions and PLGA solutions were infiltrated into macro-poresof β-TCP scaffold, and then the whole scaffolds were vacuum freeze-dried andvacuum treat respectively to improve the mechanical strength and pore structure. Themacro-pores of scaffold were almost full of polymers after the former treatment, whilethe macro-pores of scaffold were saved after the latter treatment. The toughness ofcomposite scaffolds was improved and Gelatin/β-TCP scaffold has the bestmechanical strength. The compressive strength of the Gelatin/β-TCP scaffold is3.18±0.55MPa, and the switch displacement is50%.While the compressive strengthof the PLGA/β-TCP scaffold is2.25±0.15MPa, and the switch displacement is30%.This scaffold may be used in repair of bone defect.