Hydroxyapatite-silica (HA-SiO 2 ) scaffolds with different SiO 2 content (0, 2, 5 and 10 wt.% SiO 2 ) were fabricated by freeze casting. After sintering, the scaffolds maintained the interconnected unidirectional pore channels by removing the frozen ice crystals via sublimation. X-ray diffraction (XRD) analysis indicated that SiO 2 promoted the decomposition of HA to tricalcium phosphate (TCP), comprised of α-TCP and β-TCP, which became more apparent with the increase of SiO 2 content. The microstructure observation of scanning electron microscope (SEM) showed that the scaffolds surface feature had great changes in terms of grain size and grain boundary with the addition of SiO 2 . Moreover, the addition of SiO 2 could increase the porosity and pore size of the scaffolds, even allowing it to reach a maximum as the SiO 2 content increased to 5 wt.%. Compression tests investigated the variation in the compressive strength of the scaffolds with the increase in the SiO 2 content, which showed first decreasing and then increasing behavior. In vitro evaluation results in simulated body fluid (1.5×SBF) revealed that the introduction of SiO 2 enhanced the growth rate of bone-like layer, especially the scaffold with 5 wt.% SiO 2 , which exhibited faster growth rate of bone-like layer than the other scaffolds. The XRD and fourier transformed infrared spectroscopy (FT-IR) characterization confirmed that the bone-like layer formed on the scaffold surface was a carbonate-containing hydroxyapatite bone-like layer.

中文翻译：

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冷冻铸造羟基磷灰石-二氧化硅支架的微观结构、相组成和体外评价

通过冷冻铸造制造具有不同 SiO 2 含量（0、2、5 和 10 wt.% SiO 2 ）的羟基磷灰石-二氧化硅（HA-SiO 2 ）支架。烧结后，支架通过升华去除冻结的冰晶来保持相互连接的单向孔道。X射线衍射（XRD）分析表明，SiO 2 促进HA分解为由α-TCP和β-TCP组成的磷酸三钙（TCP），随着SiO 2 含量的增加，这种分解变得更加明显。扫描电子显微镜（SEM）的微观结构观察表明，随着SiO 2 的加入，支架表面特征在晶粒尺寸和晶界方面发生了很大变化。此外，SiO 2 的添加可以增加支架的孔隙率和孔径，甚至当SiO 2 含量增加到5 wt.% 时，它甚至可以达到最大值。压缩测试研究了支架的抗压强度随 SiO 2 含量增加的变化，其表现出先降低然后增加的行为。模拟体液（1.5×SBF）体外评价结果表明，SiO 2 的引入提高了类骨层的生长速度，尤其是含有5 wt.% SiO 2 的支架，其骨样层的生长速度较快。层比其他脚手架。XRD 和傅立叶变换红外光谱 (FT-IR) 表征证实在支架表面形成的类骨层是含碳酸盐的羟基磷灰石类骨层。模拟体液（1.5×SBF）体外评价结果表明，SiO 2 的引入提高了类骨层的生长速度，尤其是含有5 wt.% SiO 2 的支架，其骨样层的生长速度较快。层比其他脚手架。XRD 和傅立叶变换红外光谱 (FT-IR) 表征证实在支架表面形成的类骨层是含碳酸盐的羟基磷灰石类骨层。模拟体液（1.5×SBF）体外评价结果表明，SiO 2 的引入提高了类骨层的生长速度，尤其是含有5 wt.% SiO 2 的支架，其骨样层的生长速度较快。层比其他脚手架。XRD 和傅立叶变换红外光谱 (FT-IR) 表征证实在支架表面形成的类骨层是含碳酸盐的羟基磷灰石类骨层。