Zhao Wenting, Lee Thomas M H, Leung Sharon S Y, Hsing I-Ming
Bioengineering Graduate Program and Department of Chemical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR.
Langmuir. 2007 Jun 19;23(13):7143-7. doi: 10.1021/la7006843. Epub 2007 May 23.
Gold nanoparticles are one of the popular nanomaterials, widely used in biosensor applications as well as nanostructure construction. An essential attribute of these gold nanoparticles (Au-nps) is their stabilization against salt-induced aggregation. In this work, utilization of deoxyribonucleotides (dNTPs) as a tunable surface-stabilization agent for Au-nps was investigated. It was found that surfaces of Au-nps are covered by a layer of dNTPs after an adequate incubation with dNTPs solutions. Electrostatic repulsion among dNTP-coated Au-nps could prevent aggregation of Au-nps at a high salt concentration. The strength of dNTP-based protection can be manipulated by changing preparation protocols (e.g., incubation temperature, ionic strength, and ratio of Au-nps to dNTPs). Four different types of dNTPs exhibit different binding affinity to Au-nps and thus various stabilization efficiency in the order of dATP > dCTP > dGTP approximately dTTP. Moreover, this salt-induced aggregation can be reinitiated by the increase of solution temperature, which leads to a partial removal of the protective dNTP layer on Au-nps. The advantage of thermally tunable aggregation/dispersion of Au-nps mediated by dNTP adsorption offers a useful approach for the preparation of biomolecule (oligonucleotides and oligopeptides) modified nanoparticles in applications of bioassay and nanobiotechnology.
金纳米颗粒是一种广受欢迎的纳米材料，广泛应用于生物传感器以及纳米结构构建领域。这些金纳米颗粒（Au-nps）的一个基本特性是它们能够稳定存在，防止盐诱导的聚集。在这项工作中，研究了利用脱氧核糖核苷酸（dNTPs）作为Au-nps的可调谐表面稳定剂。研究发现，在与dNTPs溶液充分孵育后，Au-nps的表面被一层dNTPs覆盖。dNTP包覆的Au-nps之间的静电排斥作用可以防止在高盐浓度下Au-nps的聚集。基于dNTP的保护强度可以通过改变制备方案（如孵育温度、离子强度以及Au-nps与dNTPs的比例）来调控。四种不同类型的dNTPs对Au-nps表现出不同的结合亲和力，因此具有不同的稳定效率，顺序为dATP > dCTP > dGTP ≈ dTTP。此外，溶液温度升高可重新引发这种盐诱导的聚集，这会导致Au-nps表面的保护性dNTP层部分去除。由dNTP吸附介导的Au-nps热可调聚集/分散的优势为在生物测定和纳米生物技术应用中制备生物分子（寡核苷酸和寡肽）修饰的纳米颗粒提供了一种有用的方法。
