Re-examination of the structural properties of solid solutions SrxCa1-xCO3

Materials Research, 2007, 42(6), 1061-106

Statistical experimental design for studies of porosity and compressive strength in composite materials applied as biomaterials

Composites studied in this work are the associations of aluminosilicates and 13% of calcium phosphates. These composites present great interest. They are destined to be applied in biomedical field, particularly in orthopedic or jawbone surgery. Calcium phosphates are composed of HA (hydroxyapatite) and TCP (tricalcic phosphate). The success of synthesised bony biomaterials depends on two determinant factors: the porosity (which facilitate the cells deposition and the vascularisation) and the compressive strength (which permits the support of body charge). In this way, a statistical experimental design was employed to quantify the influence of these two synthesis parameters. It concerns the effect of the K2O/SiO2 molecular ratio (X1) and the effect of the calcium phosphate (HA/TCP) weight % (X2). The K2O/SiO2 molecular ratio characterises the synthesis of the aluminosilicate. It varies between two limit levels: the stoichiometric ratio K2O/SiO2 = 0.54 corresponding to: $X_{1 }= - 1$ and the ratio K2O/SiO2 = 0.80 corresponding to $X_{1 }= 1$. In bony biomaterials field, various calcium phosphates are commonly used as biomaterials. In our previous works, the influence of the commercial hydroxyapatite HA and tri-calcium phosphate TCP (13 wt%) addition was investigated. To study the effect of calcium phosphate composition, the weight percentage of mixing HA and TCP varied between two levels: the composite aluminosilicate with 13 wt% of HA ($X_{2 }= -1$) and the composite aluminosilicate with 13 wt% of TCP ($X_{2 }= 1$). Eight samples were studied. The statistical experimental design predicted answer surfaces for compressive strength and percentage of porosity. After the validation of models, it was possible to determine composite which presents best compromise between percentage of porosity and compressive strength. This composite will be evaluated by “in-vitro” and “in-vivo” studies to investigate its potential for forthcoming applied as biomaterial

“In vitro” bioactivity of melt-derived glass 46S6 doped with magnesium

Journal of Biomedical Materials Research Part A (JBMR-A), 2008, 4, 1087 – 109

Calcification mechanism and bony bonding studies of CaCO3 and composite aluminosilicate calcium phosphate applied as biomaterials by using radioactivation methods

J. Radioanalytical and Nucl Chem., 2007, 274, n° 2, 421-42

MAS-NMR studies of geopolymer heat-treated for applications in biomaterials field

Journal of Materials Science (J. Mat. Sci)., 2007, 42, 3092-309

Comparison of the bony remodelling of two synthetic biomaterials: aragonite 55% and aragonite 55% with active substance

Biomed. Mater., 2007, 2, 65-7

Thermal behaviour of composites aluminosilicate-calcium phosphates

International audienceA new type of aluminosilicate matrix calcium phosphate crystallites composites (ACPC) was synthesized and studied for osseous bone applications. The room temperature synthesis of the aluminosilicate matrix and composites was described. Thermal treatments of compounds allowed the adaptability of some parameters (pH, porosity and mechanical properties). Structure of heat treated composites were characterized by XRD and FTIR. The influence of thermal treatment on the mechanical properties, the porosity and the pH was studied for two temperatures (250 and 500degreesC). Results evidenced the ability to control the pH, the high level of porosity (approximate to70%) and the good mechanical properties, allowing to consider that ACPC are potential biomaterials for osseous bone application

A synthetic aragonite-based bioceramic: influence of process parameters on porosity and compressive strength

International audienceWe investigate the influence of process parameters such as weight fraction and particle size of pore-former, and isostatic pressure, on porosity and compressive strength of non-sintered porous calcium carbonate biomaterials compacted at high pressure in uniaxial or isostatic mode. Experiment design and results analysis are performed according to a two-level 2(k) factorial design method (FDM). Results indicate that only the weight fraction of pore-former (wt fpf) influences significantly the porosity and the compressive strength. The porosity P, is described by a linear function of wt fpf, and the compressive strength sigma (comp), by, an exponential one. For materials compacted tinder Uniaxial pressing: P (vol%) = 33.7 + 85.4 (wt fpf) and sigma (comp) (MPa) = 28.8 e(-9.2(wt) (fpf)) with 0.1 less than or equal to wt fpf less than or equal to 0.3. For materials compacted in isostatic mode: P (vol%) = 33.9 + 82.1 (wt fpf) and sigma (comp) (MPa) = 24.0 e(-7.0(wt) (fpf)) with 0.15 less than or equal to wt fpf less than or equal to 0.35, The pore-former particle size has no significant influence on both properties. The increase in isostatic pressure provides slightly lower porosity and better compressive strength. For a fixed fraction of pore-former, isostatic pressing leads to a better compressive strength than uniaxial pressing. This study indicates that, for a constant amount of pore former, the size of macropores can be adjusted to reach optimal bone-ingrowth without change in compressive strength. (C) 2001 Elsevier Science Ltd. All rights reserved

Effects of Mg and Zn on the surface of doped melt-derived glass for biomaterials applications

Applied Surface Science, 2008, 255, 391 – 39