Are bidentate ligands really better than monodentate ligands for nanoparticles?
Are bidentate ligands really better than monodentate ligands for nanoparticles?
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对于纳米颗粒来说，双齿配体真的比单齿配体更好吗？
DOI：
10.1021/nl4023176
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发表时间：
2013
期刊：
影响因子：
10.8
通讯作者：
Heyes,ColinD
中科院分区：
文献类型：
--
作者：
Takeuchi,Hiroko;Omogo,Benard;Heyes,ColinD
配位配体被广泛用于改变纳米颗粒的溶解度和反应性以用于随后的生物缀合。虽然长期的胶体稳定性增强，通过使用双齿的单齿的配位体，其他性能，如目标分子的非特异性吸附和配体交换尚未量化。在这项研究中，我们修改了近红外染料作为一个高度敏感的报告，非特异性结合的硫醇化的目标分子的纳米粒子表面功能化与单齿或双齿配位体。具体而言，我们分析了非特异性结合机制的量子点（QD）通过拟合的吸附曲线的希尔方程和参数被用来提供一个微观图片配体密度和不稳定性如何控制非特异性吸附。令人惊讶的是，双齿配体在低目标/QD比率下抑制吸附到QD表面方面较差，尽管它们随着比率增加而变得更好，但仅当纳米颗粒表面积足够大以克服空间效应时。这一结果强调了配体密度和不稳定性之间的平衡取决于配体的配位性质，并控制溶液中的分子如何与纳米颗粒表面配位。这些结果将在纳米生物医学，生物共轭，单分子光谱学，自组装和纳米（光）催化，其中非特异性和特异性表面相互作用发挥重要作用的一系列应用的重大影响。作为一个例子，我们测试了单齿和双齿官能化纳米颗粒抵抗含有游离巯基的IgG抗体以1：1 QD/IgG比率非特异性吸附的能力，并发现具有单齿配体的QD确实导致较低的非特异性吸附。
Coordinating ligands are widely used to vary the solubility and reactivity of nanoparticles for subsequent bioconjugation. Although long-term colloidal stability is enhanced by using bidentate coordinating ligands over monodentate ones, other properties such as nonspecific adsorption of target molecules and ligand exchange have not been quantified. In this study, we modified a near-infrared dye to serve as a highly sensitive reporter for nonspecific binding of thiolated target molecules to nanoparticle surfaces that are functionalized with monodentate or bidentate coordinated ligands. Specifically, we analyzed nonspecific binding mechanisms to quantum dots (QDs) by fitting the adsorption profiles to the Hill equation and the parameters are used to provide a microscopic picture of how ligand density and lability control nonspecific adsorption. Surprisingly, bidentate ligands are worse at inhibiting adsorption to QD surfaces at low target/QD ratios, although they become better as the ratio increases, but only if the nanoparticle surface area is large enough to overcome steric effects. This result highlights that a balance between ligand density and lability depends on the dentate nature of the ligands and controls how molecules in solution can coordinate to the nanoparticle surface. These results will have major implications for a range of applications in nanobiomedicine, bioconjugation, single molecule spectroscopy, self-assembly, and nano(photo)catalysis where both nonspecific and specific surface interactions play important roles. As an example, we tested the ability of monodentate and bidentate functionalized nanoparticles to resist nonspecific adsorption of IgG antibodies that contained free thiol groups at a 1:1 QD/IgG ratio and found that QDs with monodentate ligands did indeed result in lower nonspecific adsorption.