Zhang Y, Zhang M
Department of Materials Science & Engineering, 302L Roberts Hall, University of Washington, Seattle, WA 98195-2120, USA.
J Biomed Mater Res. 2001 Jun 5;55(3):304-12. doi: 10.1002/1097-4636(20010605)55:3<304::aid-jbm1018>3.0.co;2-j.
Chitosan scaffolds reinforced by beta-tricalcium phosphate (beta-TCP) and calcium phosphate invert glass were fabricated with a low-cost, bioclean freeze-drying technique via thermally induced phase separation. The microstructure, mechanical performance, biodegradation, and bioactivity of the scaffolds were studied. The composite scaffolds were macroporous, and the pore structures of the scaffolds with beta-TCP and the glass appeared very different. Both the compressive modulus and yield strength of the scaffolds were greatly improved, and reinforced microstructures were achieved. The bioactivity tests showed a continuous decrease in both Ca and P concentrations of a simulated body fluid (SBF) after the scaffolds with beta-TCP were immersed in the SBF for more than 20 h, which suggests that an apatite layer might be formed on the scaffolds. However, the same was not observed for the pure chitosan scaffolds or the scaffolds incorporated with the glass. This was further confirmed by micrographs from scanning electron microscopy. This study suggests that the desirable pore structure, biodegradation rate, and bioactivity of the composite scaffolds might be achieved through controlling the ratio of chitosan and calcium phosphates or beta-TCP and the glass.
通过热致相分离，采用低成本、生物洁净的冷冻干燥技术制备了由β-磷酸三钙（β-TCP）和磷酸钙反相玻璃增强的壳聚糖支架。研究了支架的微观结构、力学性能、生物降解性和生物活性。复合支架为大孔结构，含β-TCP和玻璃的支架的孔结构差异很大。支架的压缩模量和屈服强度均得到显著提高，并实现了增强的微观结构。生物活性测试表明，含β-TCP的支架在模拟体液（SBF）中浸泡20 h以上后，SBF中的钙和磷浓度持续下降，这表明支架上可能形成了磷灰石层。然而，纯壳聚糖支架或含玻璃的支架未观察到同样现象。扫描电子显微镜照片进一步证实了这一点。本研究表明，通过控制壳聚糖与磷酸钙或β-TCP与玻璃的比例，可能实现复合支架理想的孔结构、生物降解率和生物活性。
