title: Silicon-stabilized α-tricalcium phosphate and its use in a calcium phosphate cement: characterization and cell response.
abstract: α-Tricalcium phosphate (α-TCP) is widely used as a reactant in calcium phosphate cements. This work aims at doping α-TCP with silicon with a twofold objective. On the one hand, to study the effect of Si addition on the stability and reactivity of this polymorph. On the other, to develop Si-doped cements and to evaluate the effect of Si on their in vitro cell response. For this purpose a calcium-deficient hydroxyapatite was sintered at 1250°C with different amounts of silicon oxide. The high temperature polymorph α-TCP was stabilized by the presence of silicon, which inhibited reversion of the β→α transformation, whereas in the Si-free sample α-TCP completely reverted to the β-polymorph. However, the β-α transformation temperature was not affected by the presence of Si. Si-α-TCP and its Si-free counterpart were used as reactants for a calcium phosphate cement. While Si-α-TCP showed faster hydrolysis to calcium-deficient hydroxyapatite, upon complete reaction the crystalline phases, morphology and mechanical properties of both cements were similar. An in vitro cell culture study, in which osteoblast-like cells were exposed to the ions released by both materials, showed a delay in cell proliferation in both cases and stimulation of cell differentiation, more marked for the Si-containing cement. These results can be attributed to strong modification of the ionic concentrations in the culture medium by both materials. Ca-depletion from the medium was observed for both cements, whereas continuous Si release was detected for the Si-containing cement.
authors.affiliation: Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering, Technical University of Catalonia (UPC), Avenida Diagonal 647, E08028 Barcelona, Spain.
authors.forename: Gemma
authors.initials: G
authors.lastname: Mestres
authors.forename: Clemence
authors.initials: C
authors.lastname: Le Van
authors.forename: Maria-Pau
authors.initials: MP
authors.lastname: Ginebra
mesh_terms: D001843:Bone Cements / Q000737:chemistry / Q000494:pharmacology; D002130:Calcium Phosphates / Q000737:chemistry / Q000494:pharmacology; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects*; D006358:Hot Temperature; D006801:Humans; D006868:Hydrolysis / Q000187:drug effects; D008422:Materials Testing; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism; D012825:Silicon / Q000737:chemistry / Q000494:pharmacology
chemical_list: D001843:Bone Cements; D002130:Calcium Phosphates; C485828:alpha-tricalcium phosphate; D012825:Silicon