Almirall A, Larrecq G, Delgado J A, Martínez S, Planell J A, Ginebra M P
Biomaterials Division, Department of Materials Science and Metallurgy, Biomedical Engineering Research Centre, Technical University of Catalonia (UPC), Av. Diagonal 647, E08028 Barcelona, Spain.
Biomaterials. 2004 Aug;25(17):3671-80. doi: 10.1016/j.biomaterials.2003.10.066.
The development of the new technologies of bone tissue engineering requires the production of bioresorbable macroporous scaffolds. Calcium phosphate cements are good candidate materials for the development of these scaffolds, as an alternative to the traditional porous sintered ceramics. In this work a novel two-step method, based in the foaming of an alpha-tricalcium phosphate (alpha-TCP) cement paste and its subsequent hydrolysis to a calcium deficient hydroxyapatite (CDHA) is presented. The foaming agent was a hydrogen peroxide (H2O2) solution, which decomposes in water and oxygen gas. CDHA foams, which combined an interconnected macroporosity with a high microporosity were obtained. The apatitic phase obtained by the hydrolysis reaction was more similar to the biologic one, in terms of chemical composition, crystallinity and specific surface than the hydroxyapatites obtained by sintering. The percentage of porosity in the foams reached a 66%. It was shown that it was possible to control the porosity, and pore size and shape by different processing parameters such as the liquid-to-powder ratio, the concentration of the H2O2 solution and the particle size of the powder.
骨组织工程新技术的发展需要生产可生物吸收的大孔支架。磷酸钙水泥是开发这些支架的良好候选材料，可替代传统的多孔烧结陶瓷。在这项工作中，提出了一种新颖的两步法，该方法基于α-磷酸三钙（α-TCP）水泥浆的发泡及其随后水解为缺钙羟基磷灰石（CDHA）。发泡剂是过氧化氢（H2O2）溶液，它会分解成水和氧气。获得了具有相互连通的大孔隙率和高微孔率的CDHA泡沫。通过水解反应获得的磷灰石相在化学成分、结晶度和比表面积方面比通过烧结获得的羟基磷灰石更类似于生物磷灰石。泡沫中的孔隙率百分比达到了66%。结果表明，通过不同的工艺参数，如液固比、H2O2溶液浓度和粉末粒径，可以控制孔隙率、孔径和形状。
