Laboratory of Industrial Physics, Department of Physics and Astronomy, University of Turku, Turku FI-20014, Finland.
Langmuir. 2012 Oct 2;28(39):14045-54. doi: 10.1021/la303091k. Epub 2012 Sep 20.
Thermally carbonized porous silicon (TCPSi) microparticles were chemically modified with organofunctional alkoxysilane molecules using a silanization process. Before the silane coupling, the TCPSi surface was activated by immersion in hydrofluoric acid (HF). Instead of regeneration of the silicon hydride species, the HF immersion of silicon carbide structure forms a silanol termination (Si-OH) on the surface required for silanization. Subsequent functionalization with 3-aminopropyltriethoxysilane provides the surface with an amine (-NH(2)) termination, while the SiC-type layer significantly stabilizes the functionalized structure both mechanically and chemically. The presence of terminal amine groups was verified with FTIR, XPS, CHN analysis, and electrophoretic mobility measurements. The overall effects of the silanization to the morphological properties of the initial TCPSi were analyzed and they were found to be very limited, making the treatment effects highly predictable. The maximum obtained number of amine groups on the surface was calculated to be 1.6 groups/nm(2), corresponding to 79% surface coverage. The availability of the amine groups for further biofunctionalization was confirmed by successful biotinylation. The isoelectric point (IEP) of amine-terminated TCPSi was measured to be at pH 7.7, as opposed to pH 2.6 for untreated TCPSi. The effects of the surface amine termination on the cell viability of Caco-2 and HT-29 cells and on the in vitro fenofibrate release profiles were also assessed. The results indicated that the surface modification did not alter the loading of the drug inside the pores and also retained the beneficial enhanced dissolution characteristics similar to TCPSi. Cellular viability studies also showed that the surface modification had only a limited effect on the biocompatibility of the PSi.
热解碳化硅（TCPSi）微球经硅烷化反应用有机官能团烷氧基硅烷分子进行化学修饰。在硅烷偶联之前，TCPSi 表面通过浸入氢氟酸（HF）来进行活化。HF 浸碳化硅结构代替硅氢化物物种的再生，在表面上形成硅醇端基（Si-OH），这是硅烷化所必需的。随后用 3-氨丙基三乙氧基硅烷进行功能化，使表面带有胺（-NH（2））端基，而 SiC 型层在机械和化学上都显著稳定了功能化结构。通过傅里叶变换红外光谱（FTIR）、X 射线光电子能谱（XPS）、CHN 分析和电泳迁移率测量验证了末端胺基的存在。分析了硅烷化对初始 TCPSi 形态性能的整体影响，发现影响非常有限，使处理效果具有高度可预测性。计算得到表面上最多可获得的胺基数为 1.6 个/纳米（2），对应于 79%的表面覆盖率。通过成功的生物素化，证实了胺端 TCPSi 上胺基的可用性可用于进一步的生物功能化。胺端 TCPSi 的等电点（IEP）测量为 pH7.7，而未经处理的 TCPSi 的 IEP 为 pH2.6。还评估了表面胺端对 Caco-2 和 HT-29 细胞活力的影响以及体外非诺贝特释放曲线。结果表明，表面修饰并没有改变药物在孔内的负载量，并且还保留了类似于 TCPSi 的有益的增强溶解特性。细胞活力研究还表明，表面修饰对 PSi 的生物相容性只有有限的影响。
