Measuring the grafting density of nanoparticles in solution by analytical ultracentrifugation and total organic carbon analysis.
Measuring the grafting density of nanoparticles in solution by analytical ultracentrifugation and total organic carbon analysis.
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通过分析超速离心和总有机碳分析测量溶液中纳米颗粒的嫁接密度。
DOI：
10.1021/ac301980a
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发表时间：
2012-11-06
影响因子：
7.4
通讯作者：
Colvin VL
中科院分区：
文献类型：
--
作者：
Benoit DN;Zhu H;Lilierose MH;Verm RA;Ali N;Morrison AN;Fortner JD;Avendano C;Colvin VL
纳米颗粒的许多溶液相性质，例如它们的胶体稳定性和流体动力学直径，由结合到颗粒表面的稳定基团的数目（即，接枝密度）。在这里，我们展示了两种技术，分析超滤（AUC）和总有机碳分析（TOC），可以分别应用于测量这个参数。AUC直接测量纳米颗粒-聚合物缀合物的密度，而TOC提供其水性分散体的总碳含量。当这些技术被应用到模型金纳米粒子与硫醇化聚（乙二醇），测量接枝密度在一个范围内的聚合物链长度，聚合物浓度，和纳米粒子直径同意在20%以内。此外，测得的接枝密度与固体共轭物样品的热重分析确定的聚合物含量相关。使用这些工具，我们研究的颗粒核心直径，聚合物链长，和聚合物溶液浓度依赖的纳米粒子接枝密度在金纳米粒子-聚（乙二醇）共轭体系。
Many of the solution phase properties of nanoparticles, such as their colloidal stability and hydrodynamic diameter, are governed by the number of stabilizing groups bound to the particle surface (i.e., grafting density). Here we show how two techniques, analytical ultracentrifugation (AUC) and total organic carbon analysis (TOC), can be applied separately to the measurement of this parameter. AUC directly measures the density of nanoparticle–polymer conjugates while TOC provides the total carbon content of its aqueous dispersions. When these techniques are applied to model gold nanoparticles capped with thiolated poly(ethylene glycol), the measured grafting densities across a range of polymer chain lengths, polymer concentrations, and nanoparticle diameters agree to within 20%. Moreover, the measured grafting densities correlate well with the polymer content determined by thermogravimetric analysis of solid conjugate samples. Using these tools, we examine the particle core diameter, polymer chain length, and polymer solution concentration dependence of nanoparticle grafting densities in a gold nanoparticle–poly(ethylene glycol) conjugate system.