Surface modification of magnetic nanoparticles with alkoxysilanes and their application in magnetic bioseparations
Surface modification of magnetic nanoparticles with alkoxysilanes and their application in magnetic bioseparations
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作者：
Bruce, IJ;Sen, T
基于(氨丙基)三乙氧基硅烷(APTS)的缩合，建立了一种在二氧化硅包覆的磁铁矿复合纳米颗粒表面引入胺基的通用且廉价的方法。观察到该过程对一系列变量敏感，并且在不同反应条件下合成了一系列硅烷表面改性纳米粒子，即溶剂体系[水、四氢呋喃（THF）、乙醇或它们的1:1混合物]、反应时间（1至24小时）和温度（18、50和70摄氏度），以水为催化剂和硅烷 0.2% 或 2% (w/v)，以尝试优化该过程。各种反应的产物在用单链寡核苷酸捕获序列修饰之前，根据其表面 NH2 基团、形态以及 DNA 结合和洗脱特性进行表征。据观察，仔细控制温度、时间和溶剂条件对于纳米颗粒的最佳硅烷化非常重要，在我们的实验中，当悬浮液中的颗粒的硅烷化涉及使用水作为溶剂和 0.2% (w/v) 的 APTS 时，并且当反应在室温下进行 5 小时，然后对颗粒悬浮液进行超声处理时，可以获得最佳结果。所产生的材料用于实验中，在与寡核苷酸嫁接后通过杂交选择性捕获互补核酸序列。据观察，捕获实验中寡核苷酸修饰颗粒的效率与支持物表面存在的胺基团的原始密度直接相关。结果表明，在规定的优化条件下通过硅烷化可以对纳米粒子进行表面工程。这种方法可以扩展到此类表面和具有其他官能团的其他材料的活化。
A versatile and inexpensive method for the introduction of amine groups onto the surface of silica-coated magnetite composite nanoparticles has been established based on the condensation of (aminopropyl)triethoxysilane (APTS). The process was observed to be sensitive to a range of variables, and a range of silane surface-modified nanoparticles was synthesized under various reaction conditions, that is, solvent systems [water, tetrahydrofuran (THF), ethanol, or 1:1 mixtures of them], reaction times (from I to 24 h), and temperatures (18, 50, and 70 degrees C), with water as the catalyst and silane at either 0.2% or 2% (w/v) in an attempt to optimize the process. The products of the various reactions were characterized in terms of their possession of surface-NH2 groups, morphologies, and properties with respect to DNA binding and elution before being modified with a single-stranded oligonucleotide capture sequence. It was observed that careful manipulation of temperature, time, and solvent conditions was important for optimal silanization of the nanoparticles, and in our experiments best results were obtained when silanization of the particles in suspension involved use of water as the solvent and APTS at 0.2% (w/v) and when the reaction was conducted at room temperature for 5 h and was preceded by ultrasonication of the particle suspension. The materials produced were used in experiments to selectively capture complementary nucleic acid sequences by hybridization after grafting with an oligonucleotide. The efficiency of the oligonucleotide-modified particles in the capture experiments was observed to be directly related to the original density of amine groups present at the surface of the support. The results indicate that surface engineering of the nanoparticles was possible by silanization under defined, optimized conditions. This approach could be extended to the activation of such surfaces and other materials with other functional groups.