Li Xinxin, Barua Sutapa, Rege Kaushal, Vogt Bryan D
Department of Chemical Engineering, Arizona State University, Tempe, Arizona 85284, USA.
Langmuir. 2008 Oct 21;24(20):11935-41. doi: 10.1021/la801849n. Epub 2008 Sep 17.
Mesoporous materials have been proposed for use in numerous biological environments such as substrates for cell culture and controlled release for drug delivery. Although mesoporous silica synthesis is facile, recent reports (Dunphy et al. Langmuir 2003, 19, 10403; Bass et al. Chem. Mater. 2007, 19, 4349) have demonstrated instability (dissolution) of pure mesoporous silica films under biologically relevant conditions. In this work, we demonstrate a simple processing handle (pressure) to control the dissolution of mesoporous silica films that are synthesized using preformed template films and supercritical CO 2. Spectroscopic ellipsometry is utilized to quantify changes in both the film thickness and porosity; these properties provide insight into the dissolution mechanism. The pore size increases as the films are exposed to phosphate-buffered saline (PBS) through preferential dissolution at the pore wall in comparison to the film surface; a mechanism reminiscent of bulk erosion of scaffolds for drug delivery. Thin mesoporous silica film lifetimes can be extended from several hours using traditional sol-gel approaches to days by using CO 2 processing for identical film thickness. Osteoblast attachment and viability on these films was found to correlate with their increased stability. This enhanced stability opens new possibilities for the utilization of mesoporous silica for biological applications, including drug delivery and tissue engineering.
介孔材料已被提议用于众多生物环境中，如细胞培养的基质和药物递送的控释。尽管介孔二氧化硅的合成很容易，但最近的报道（邓菲等人，《朗缪尔》，2003年，第19卷，第10403页；巴斯等人，《化学材料》，2007年，第19卷，第4349页）表明，纯介孔二氧化硅薄膜在生物相关条件下不稳定（溶解）。在这项工作中，我们展示了一种简单的处理方法（压力）来控制使用预制模板膜和超临界二氧化碳合成的介孔二氧化硅薄膜的溶解。利用光谱椭偏仪来量化薄膜厚度和孔隙率的变化；这些特性有助于深入了解溶解机制。与薄膜表面相比，由于孔壁处的优先溶解，当薄膜暴露于磷酸盐缓冲盐水（PBS）时，孔径会增大；这一机制类似于药物递送支架的整体侵蚀。对于相同薄膜厚度，通过使用二氧化碳处理，薄介孔二氧化硅薄膜的寿命可以从使用传统溶胶 - 凝胶方法的几小时延长至数天。发现成骨细胞在这些薄膜上的附着和活力与其稳定性的提高相关。这种增强的稳定性为介孔二氧化硅在生物应用中的利用开辟了新的可能性，包括药物递送和组织工程。
