Department of Chemistry, Dalhousie University, 6274 Coburg Road, Halifax, NS, Canada.
Division of Materials Science, California Institute of Technology, Pasadena, CA, 91125, USA.
Chemistry. 2018 Jun 4;24(31):7913-7920. doi: 10.1002/chem.201705818. Epub 2018 May 8.
In this study, the influence of metals (Mg, Al, and Ca) and reaction conditions (time, temperature, and metal grain size) on the metallothermic reduction of Stöber silica nanoparticles (NPs) to form porous Si has been explored. Mg metal was found to be an effective reducing agent even at temperatures below its melting point; however, it also induced a high degree of structural damage and morphology change. Al was effective in reducing silica NPs only at its melting point or above, but the resulting particles retained a higher degree of structural morphology as compared to those reduced using Mg. Ca was found to be ineffective in reducing silica. A new reductant, a mixture of 70 % Mg and 30 % Al, was found to induce the least amount of morphology change, and the reactions proceeded at a temperature (450 °C) lower than those required with Mg or Al individually. Furthermore, porous Si NPs obtained using Mg, Al, and the mixture of 70 % Mg and 30 % Al as reductants have been investigated as carriers for ibuprofen loading and release. Porous Si obtained from reductions with Mg and the Mg/Al mixture showed higher drug loading and a sustained drug release profile, whereas porous Si obtained from Al reduction had lower loading and showed a conventional release profile over 24 h.
在这项研究中，探索了金属（Mg、Al 和 Ca）和反应条件（时间、温度和金属粒度）对 Stöber 二氧化硅纳米颗粒（NPs）进行金属热还原形成多孔硅的影响。研究发现，即使在低于其熔点的温度下，Mg 金属也是一种有效的还原剂；然而，它也会导致高度的结构损伤和形态变化。Al 仅在其熔点或以上时才有效还原二氧化硅 NPs，但与使用 Mg 还原的颗粒相比，所得颗粒保留了更高程度的结构形态。Ca 被发现对二氧化硅没有还原作用。发现一种新的还原剂，即 70%Mg 和 30%Al 的混合物，引起的形态变化最小，反应温度（450°C）低于单独使用 Mg 或 Al 时所需的温度。此外，还研究了使用 Mg、Al 和 70%Mg 和 30%Al 的混合物作为还原剂获得的多孔硅 NPs 作为布洛芬负载和释放的载体。用 Mg 和 Mg/Al 混合物还原得到的多孔硅显示出更高的药物负载和持续的药物释放曲线，而用 Al 还原得到的多孔硅负载较低，在 24 小时内显示出常规释放曲线。
