Objective: To investigate the preparation and properties of the novel silica (SiO 2)/hydroxyapatite (HAP) whiskers porous ceramics scaffold.
Methods: The HAP whiskers were modified by the SiO 2 microspheres using the Stöber method. Three types of SiO 2/HAP whiskers were fabricated under different factors (for the No.1 samples, the content of tetraethoxysilane, stirring time, calcination temperature, and soaking time were 10 mL, 12 hours, 560℃, and 0.5 hours, respectively; and in the No.2 samples, those were 15 mL, 24 hours, 650℃, and 2 hours, respectively; while those in the No.3 samples were 20 mL, 48 hours, 750℃, and 4 hours, respectively). The phase and morphology of the self-made HAP whisker and 3 types of SiO 2/HAP whiskers were detected by the X-ray diffraction analysis and scanning electron microscopy. Taken the self-made HAP whisker and 3 types of SiO 2/HAP whiskers as raw materials, various porous ceramic materials were prepared using the mechanical foaming method combined with extrusion molding method, and the low-temperature heat treatment. The pore structure of porous ceramics was observed by scanning electron microscopy. Its porosity and pore size distribution were measured. And further the axial compressive strength was measured, and the biodegradability was detected by simulated body fluid. Cell counting kit 8 method was used to conduct cytotoxicity experiments on the extract of porous ceramics.
Results: The SiO 2 microspheres modified HAP whiskers and its porous ceramic materials were prepared successfully, respectively. In the SiO 2/HAP whiskers, the amorphous SiO 2 microspheres with a diameter of 200 nm, uniform distribution and good adhesion were attached to the surface of the whiskers, and the number of microspheres was controllable. The apparent porosity of the porous ceramic scaffold was about 78%, and its pore structure was composed of neatly arranged longitudinal through-holes and a large number of micro/nano through-holes. Compared with HAP whisker porous ceramic, the axial compressive strength of the SiO 2/HAP whisker porous ceramics could reach 1.0 MPa, which increased the strength by nearly 4 times. Among them, the axial compressive strength of the No.2 SiO 2/HAP whisker porous ceramic was the highest. The SiO 2 microspheres attached to the surface of the whiskers could provide sites for the deposition of apatite. With the content of SiO 2 microspheres increased, the deposition rate of apatite accelerated. The cytotoxicity level of the prepared porous ceramics ranged from 0 to 1, without cytotoxicity.
Conclusion: SiO 2/HAP whisker porous ceramics have good biological activity, high porosity, three-dimensional complex pore structure, good axial compressive strength, and no cytotoxicity, which make it a promising scaffold material for bone tissue engineering.
目的: 探讨一种新型二氧化硅（SiO 2）/羟基磷灰石（hydroxyapatite，HAP）晶须多孔陶瓷支架材料的制备及其性能。.
方法: 采用Stöber法对HAP晶须表面进行SiO 2微球改性，采用不同条件制备3种SiO 2/HAP晶须（1号SiO 2/HAP晶须正硅酸乙酯、搅拌时间、煅烧温度、保温时间分别为10 mL、12 h、560℃、0.5 h，2号SiO 2/HAP晶须分别为15 mL、24 h、650℃、2 h，3号SiO 2/HAP晶须分别为20 mL、48 h、750℃、4 h）。对自制HAP晶须和3种SiO 2/HAP晶须进行物相与形貌分析（包括X射线衍射分析和扫描电镜观察）。采用机械发泡法结合挤出成型法，以自制HAP晶须和3种SiO 2/HAP晶须为原料，低温热处理方式制备多孔陶瓷材料。对多孔陶瓷进行扫描电镜观察及孔隙率和孔径分布检测，并进行轴向抗压强度测定，采用模拟体液检测其生物降解性能，采用细胞计数试剂盒8法对多孔陶瓷浸提液进行细胞毒性实验。.
结果: 成功对HAP晶须表面进行SiO 2微球改性，并以此为原料制备了多孔陶瓷材料。SiO 2/HAP晶须中SiO 2微球为非结晶态，球径约 200 nm，微球数量可控，分布均匀且附着性较好。SiO 2/HAP晶须多孔陶瓷支架的显气孔率约为78%，其孔隙结构由排列整齐的纵向直通孔及大量微纳米级贯通孔构成。与HAP晶须多孔陶瓷相比，SiO 2/HAP晶须多孔陶瓷的轴向抗压强度可达1.0 MPa，强度提高了近4倍；其中2号SiO 2/HAP晶须多孔陶瓷的轴向抗压强度最大。HAP晶须表面附着的SiO 2微球能为磷灰石的沉积提供位点；SiO 2微球含量越高，磷灰石的沉积速率越快。制备的多孔陶瓷细胞毒性等级为0～1级，无细胞毒性。.
结论: SiO 2/HAP晶须多孔陶瓷具有良好的生物活性、高孔隙率、三维复合孔隙结构、较好的轴向抗压强度以及无细胞毒性，是一种有应用前景的骨组织工程支架材料。.
Keywords: Silica microspheres; extrusion molding; hydroxyapatite whisker; mechanical foaming; porous ceramics.