Carrodeguas R G, De Aza A H, De Aza P N, Baudín C, Jiménez J, López-Bravo A, Pena P, De Aza S
Centro de Biomateriales, Universidad de La Habana, Ave. Universidad s/n e/G y Ronda, Apdo. Postal 6130, 10600, La Habana, Cuba, and Hospital Provincial de Avila, Spain.
J Biomed Mater Res A. 2007 Nov;83(2):484-95. doi: 10.1002/jbm.a.31216.
Pseudowollastonite ceramics (beta-CaSiO3) from synthetic and natural sources were assessed with regard to their properties relevant to biomedical applications. Synthetic and natural CaSiO3 powders, with average particle size of 1.6 and 13.2 microm, respectively, were first employed. Powders were pressed and sintered at 1400 degrees C for 2 h. Pseudowollastonite was the only crystalline phase in sintered materials. Glassy phase, eight times more abundant in sintered natural wollastonite (SNW) than in the synthetic one (SSW), was observed in grain boundaries and in triple points. Larger grains and bigger and more abundant pores were present in SNW, resulting in lower diametral tensile strength (26 MPa), than in SSW (42 MPa). However, by milling the natural wollastonite starting powder to a particle size of 2.0 microm and sintering (SNW-M), the microstructure became finer and less porous, and diametral tensile strength increased (48 MPa). Weibull modulus of SNW and SNW-M samples was twice that of the SSW. All the samples released Si and Ca ions, and removed phosphate ions from simulated body fluid in similar amounts and were completely coated by apatite-like spherules after soaking in simulated body fluid for 3 wk. The aqueous extracts from all samples studied were not cytotoxic in a culture of human fibroblastic cells. No differences in fibroblast-like human cells adhesion and proliferation were observed between samples. According to the obtained results, properly processed pseudowollastonite bioceramics, obtained from the natural source, exhibit the same in vitro behavior and better performance in terms of strength and reliability than do the more expensive synthetic materials.
对来自合成和天然来源的假硅灰石陶瓷（β-CaSiO₃）在与生物医学应用相关的性能方面进行了评估。首先使用了平均粒径分别为1.6微米和13.2微米的合成和天然CaSiO₃粉末。将粉末压制并在1400℃下烧结2小时。假硅灰石是烧结材料中唯一的晶相。在晶界和三相点观察到玻璃相，其在烧结天然硅灰石（SNW）中的含量比合成硅灰石（SSW）中的多八倍。SNW中存在更大的晶粒以及更大且更多的孔隙，导致其径向拉伸强度（26MPa）低于SSW（42MPa）。然而，通过将天然硅灰石起始粉末研磨至2.0微米的粒径并进行烧结（SNW-M），微观结构变得更细且孔隙更少，径向拉伸强度增加（48MPa）。SNW和SNW-M样品的威布尔模量是SSW的两倍。所有样品都释放Si和Ca离子，并从模拟体液中去除相似量的磷酸根离子，在模拟体液中浸泡3周后完全被类磷灰石小球覆盖。所研究的所有样品的水提取物在人成纤维细胞培养中无细胞毒性。在样品之间未观察到成纤维样人细胞粘附和增殖的差异。根据所得结果，从天然来源获得的经过适当加工的假硅灰石生物陶瓷在体外表现出相同的行为，并且在强度和可靠性方面比更昂贵的合成材料具有更好的性能。
