Preparation Of Beta-tricalcium Phosphate / Porous Bioactive Glass Composite Scaffolds Of Intensive Research

Many bone graft materials have been applied to repair bone defective and lost bone. Tissue engineering has shown great promise as a viable alternative to calcium phosphate-based bone graft solutions due to its use of biocompatible, biodegradable porous scaffolds as support systems for cellular attachment, proliferation, migration. However, because of their natural brittleness, calcium phosphate-based bone grafts, in a porous form, have very low strength and toughness.Thus, despite their favorable biogical properties, the poor mechanical properties of these grafts have severely hindered their clinical applicationsTowards this end, three-dimensional (3D), highly porous, mechanically competent, bioactive and biodegradable scaffolds were fabricated by the physical foaming technique usingβ-tricalcium phosphate (TCP) as matrix, bioglasss powders as binder. First, the effects of surfactants as foaming agent on their microstructure were investigated. Then, several parameters such as the concentration of bioglass, the temperature of sintering and solid loading were investigated to control mechanical properties and microstructure of scaffolds. This thesis also seeks to further increase the mechanical strength and toughness of the scaffold by inclusion of a second phase of nano hydroxyapatite (HA) in a porousβ-TCP/Bioglass matrix and to study the mechanism involved in this enhancement.The results showed that, under an optimum process conditions, such as inclusion of 20 wt% bioglass, 55 wt% solid loading and sintering at 1000℃, scaffolds with a pore size ranging from 750～850μm can be fabricated that have an interconnected macroporous structure, which with a porosity of～55 % porosity containing 20 wt% bioglass attained a compressive strength of 4．83±0．2MPa. Under the same process conditions, the compressive strength of scaffolds increases 2．9 times up to 18．96±0．6 MPa, whose toughness is 2．3±0．08 KN/m with 4 wt% nano HA particles incorporated, which meet the need of scaffolds for load-bearing bone tissue engineering. This is not only a successful research into calcium phosphate-based scaffolds for load-bearing bone tissue engineering, but it is also an initial investigation in improving mechanical properties of porousβ-TCP/Bioglass scaffolds.