Department of Chemistry, University of Konstanz , Universitätsstr. 10, 78457 Konstanz, Germany.
Department of Physical Chemistry, University of Murcia , 30071 Murcia, Spain.
ACS Nano. 2016 Aug 23;10(8):7418-27. doi: 10.1021/acsnano.6b01377. Epub 2016 Aug 8.
Current developments in nanotechnology have increased the demand for nanocrystal assemblies with well-defined shapes and tunable sizes. DNA is a particularly well-suited building block in nanoscale assemblies because of its scalable sizes, conformational variability, and convenient self-assembly capabilities via base pairing. In hybrid materials, gold nanoparticles (AuNPs) can be assembled into nanoparticle structures with programmable interparticle distances by applying appropriate DNA sequences. However, the development of stoichiometrically defined DNA/NP structures is still challenging since product mixtures are frequently obtained and their purification and characterization is the rate-limiting step in the development of DNA-NP hybrid assemblies. Improvements in nanostructure fractionation and characterization techniques offer great potential for nanotechnology applications in general. This study reports the application of analytical ultracentrifugation (AUC) for the characterization of anisotropic DNA-linked metal-crystal assemblies. On the basis of transmission electron microscopy data and the DNA primary sequence, hydrodynamic bead models are set up for the interpretation of the measured frictional ratios and sedimentation coefficients. We demonstrate that the presence of single DNA strands on particle surfaces as well as the shape factors of multiparticle structures in mixtures can be quantitatively described by AUC. This study will significantly broaden the possibilities to analyze mixtures of shape-anisotropic nanoparticle assemblies. By establishing insights into the analysis of nanostructure mixtures based on fundamental principles of sedimentation, a wide range of potential applications in basic research and industry become accessible.
当前，纳米技术的发展使得人们对具有特定形状和可调尺寸的纳米晶体组装体的需求日益增加。由于 DNA 具有可扩展的尺寸、构象可变性以及通过碱基配对方便的自组装能力，因此它是纳米级组装体中特别适用的构建模块。在混合材料中，通过应用适当的 DNA 序列，金纳米粒子（AuNPs）可以组装成具有可编程粒子间距离的纳米粒子结构。然而，由于经常获得混合物产物，并且其纯化和表征是 DNA-NP 混合组装发展的限速步骤，因此，具有化学计量定义的 DNA/NP 结构的开发仍然具有挑战性。纳米结构分级和表征技术的改进为纳米技术的一般应用提供了巨大的潜力。本研究报告了分析超速离心（AUC）在表征各向异性 DNA 连接金属晶体组装体中的应用。基于透射电子显微镜数据和 DNA 一级序列，为解释测量的摩擦比和沉降系数，建立了水动力珠模型。我们证明，AUC 可以定量描述粒子表面上单个 DNA 链的存在以及混合物中多粒子结构的形状因子。这项研究将大大拓宽分析形状各向异性纳米粒子组装体混合物的可能性。通过基于沉降的基本原理建立对纳米结构混合物的分析见解，为基础研究和工业领域的广泛应用提供了可能。
