Shamsudin Roslinda, Abdul Azam Farah 'Atiqah, Abdul Hamid Muhammad Azmi, Ismail Hamisah
School of Applied Physics, Faculty of Science & Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia.
Materials (Basel). 2017 Oct 17;10(10):1188. doi: 10.3390/ma10101188.
The aim of this study was to prepare β-wollastonite using a green synthesis method (autoclaving technique) without organic solvents and to study its bioactivity. To prepare β-wollastonite, the precursor ratio of CaO:SiO₂ was set at 55:45. This mixture was autoclaved for 8 h and later sintered at 950 °C for 2 h. The chemical composition of the precursors was studied using X-ray fluorescence (XRF), in which rice husk ash consists of 89.5 wt % of SiO₂ in a cristobalite phase and calcined limestone contains 97.2 wt % of CaO. The X-ray diffraction (XRD) patterns after sintering showed that only β-wollastonite was detected as the single phase. To study its bioactivity and degradation properties, β-wollastonite samples were immersed in simulated body fluid (SBF) for various periods of time. Throughout the soaking period, the molar ratio of Ca/P obtained was in the range of 1.19 to 2.24, and the phase detected was amorphous calcium phosphate, which was confirmed by scanning electron microscope with energy dispersive X-ray analysis (SEM/EDX) and XRD. Fourier-transform infrared spectroscopy (FTIR) analysis indicated that the peaks of the calcium and phosphate ions increased when an amorphous calcium phosphate layer was formed on the surface of the β-wollastonite sample. A cell viability and proliferation assay test was performed on the rice husk ash, calcined limestone, and β-wollastonite samples by scanning electron microscope. For heavy metal element evaluation, a metal panel that included As, Cd, Pb, and Hg was selected, and both precursor and β-wollastonite fulfilled the requirement of an American Society for Testing and Materials (ASTM F1538-03) standard specification. Apart from that, a degradation test showed that the loss of mass increased incrementally as a function of soaking period. These results showed that the β-wollastonite materials produced from rice husk ash and limestone possessed good bioactivity, offering potential for biomedical applications.
本研究的目的是采用无有机溶剂的绿色合成方法（高压釜技术）制备β-硅灰石，并研究其生物活性。为制备β-硅灰石，将CaO:SiO₂的前驱体比例设定为55:45。将该混合物在高压釜中处理8小时，随后在950℃下烧结2小时。使用X射线荧光光谱法（XRF）研究前驱体的化学成分，其中稻壳灰含有89.5 wt%处于方石英相的SiO₂，煅烧石灰石含有97.2 wt%的CaO。烧结后的X射线衍射（XRD）图谱显示，仅检测到β-硅灰石作为单相。为研究其生物活性和降解性能，将β-硅灰石样品在模拟体液（SBF）中浸泡不同时间。在整个浸泡期间，获得的Ca/P摩尔比在1.19至2.24范围内，检测到的相为无定形磷酸钙，这通过扫描电子显微镜结合能量色散X射线分析（SEM/EDX）和XRD得到证实。傅里叶变换红外光谱（FTIR）分析表明，当β-硅灰石样品表面形成无定形磷酸钙层时，钙和磷酸根离子的峰增加。通过扫描电子显微镜对稻壳灰、煅烧石灰石和β-硅灰石样品进行了细胞活力和增殖测定试验。对于重金属元素评估，选择了包含As、Cd、Pb和Hg的金属面板，前驱体和β-硅灰石均符合美国材料与试验协会（ASTM F1538-03）标准规范的要求。除此之外，降解试验表明，质量损失随着浸泡时间的增加而逐渐增加。这些结果表明，由稻壳灰和石灰石制备的β-硅灰石材料具有良好的生物活性，在生物医学应用方面具有潜力。
