摘要：
BACKGROUND: Hydroxyapatite ceramic is one of the bioactive ceramics commonly used in clinic. Accurate regulation of the surface microstructure of hydroxyapatite ceramics is favorable for improving its biological performance, which is needed to be investigated thoroughly. OBJECTIVE: To investigate the effect of surface roughness on the wettability and protein adsorption ability of hydroxyapatite ceramic as well as mesenchymal stem cell proliferation on its surface. METHODS: Hydroxyapatite powders were synthesized by chemical precipitation method. Hydroxyapatite ceramics were produced by cold isostatic pressing of the powders and then high-temperature sintering of the obtained green compacts. After the different grinding and polishing processes, the hydroxyapatite ceramics with three distinct surface roughness were fabricated. The phase composition, microstructure, surface roughness and water contact angle of the hydroxyapatite ceramics were evaluated. Bovine serum albumin was used as the protein model to study the effect of surface roughness on protein adsorption. The in vitro cell culture was carried out to investigate the effect of surface roughness of hydroxyapatite ceramics on the growth and proliferation of rat bone marrow mesenchymal stem cells. RESULTS AND CONCLUSION: The hydroxyapatite ceramics with no surface treatment had higher surface roughness, presenting with marked undulating surface; the hydroxyapatite ceramics with surface grinding had a reduction in the surface roughness, but still had an undulating surface; and the hydroxyapatite ceramics with polishing treatment had a smooth surface. The surface roughness of the three hydroxyapatite ceramics with different surface treatment as mentioned above was 448.4, 229.9 and 18.6 nm, respectively, and there was a significant difference between them. The results of contact angle tests indicated that water contact angle of the hydroxyapatite ceramic was influenced by its surface roughness. Lower surface roughness meant larger contact angle, leading to the decreased hydrophilicity of the hydroxyapatite ceramics. The protein adsorption experiment showed that the hydroxyapatite ceramics were favorable for bovine serum albumin adsorption, and the amount of the adsorbed bovine serum albumin was dependent on the surface roughness of the ceramic as well as the initial concentration of the protein solution. The hydroxyapatite ceramics with higher surface roughness would absorb more bovine serum albumin, and the bovine serum albumin adsorption increased with the increasing initial concentration of the protein solution. The in vitro cell culture confirmed that surface roughness impacted the proliferation of rat bone marrow mesenchymal stem cells. Although the good attachment and growth of bone marrow mesenchymal stem cells were observed on the three hydroxyapatite ceramics, faster proliferation of mesenchymal stem cells occurred on the hydroxyapatite ceramics with lower and nano-scaled surface roughness was observed. Therefore, the surface roughness of hydroxyapatite ceramics exerts great effects on hydrophobicity, protein adsorption, and cell proliferation and growth.%背景:羟基磷灰石陶瓷是临床常用的生物活性陶瓷,其表面微结构的精确调控对材料的生物学性能有重要影响,需要更加深入的研究.目的:考察羟基磷灰石陶瓷表面粗糙度对材料润湿性、蛋白吸附及间充质干细胞增殖的影响.方法:采用湿化学沉淀法合成羟基磷灰石前驱粉体,冷等静压成型后高温烧结制得羟基磷灰石陶瓷;通过不同磨抛处理调控陶瓷表面粗糙度(获得3个试样:未经任何磨抛处理、精磨处理、抛光处理),测试其微观形貌、表面粗糙度和接触角.体外实验检测不同粗糙度羟基磷灰石陶瓷表面对牛血清白蛋白的吸附.将大鼠骨髓间充质干细胞分别接种于3种表面粗糙度羟基磷灰石陶瓷表面,培养1,3,5 d,CCK-8法检测细胞增殖,同时采用激光共聚焦显微镜观察陶瓷表面细胞形态.结果与结论:①未经任何磨抛处理陶瓷表面高低起伏较大,具有较高的粗糙度;与未经任何磨抛处理陶瓷相比,经过精磨处理陶瓷表面的粗糙度较降低,表面仍有一定起伏;经抛光处理的陶瓷表面平整光滑;②未经任何磨抛处理、精磨处理、抛光处理陶瓷表面的粗糙度分别为 448.4,229.9,18.6 nm,组间两两比较差异有显著性意义;③抛光处理陶瓷表面的接触角高于未经任何磨抛处理与精磨处理陶瓷(P ＜ 0.01);④羟基磷灰石陶瓷对牛血清白蛋白有较强的吸附亲和性,且受表面粗糙度和蛋白溶液初始浓度影响:表面粗糙度越大,陶瓷吸附牛血清白蛋白的量越大,且随蛋白溶液初始浓度增加而进一步增大;⑤表面粗糙度影响羟基磷灰石陶瓷表面骨髓间充质干细胞的增殖,细胞在所有羟基磷灰石陶瓷表面均表现出良好的贴附和生长状态,但在粗糙度低的陶瓷表面增殖速度更快;⑥结果表明,羟基磷灰石陶瓷表面粗糙度对其亲疏水性、蛋白吸附及细胞增殖和生长有较大影响.
