Carnerero Jose M, Jimenez-Ruiz Aila, Grueso Elia M, Prado-Gotor Rafael
Department of Physical Chemistry, Faculty of Chemistry, University of Seville. c/ Profesor García González, 1. 41012, Seville, Spain.
Phys Chem Chem Phys. 2017 Jun 21;19(24):16113-16123. doi: 10.1039/c7cp02219k.
It is well known that single-stranded DNA (ssDNA) is easily able to adsorb on citrate-capped, non-functionalized gold nanoparticles (AuNPs). However, the affinity of double-stranded DNA (dsDNA) for them is much more limited. The present work demonstrates that long dsDNA suffers from a bending conformational change when anionic nanoparticles are present in solution. A striking decrease in the persistence length of the double helix in the absence of salt is observed through dynamic light scattering (DLS), viscometric, and atomic force microscopy (AFM) methods. Long dsDNA is therefore shown to be able to interact with anionic gold nanoparticles. To date, only ssDNA detection has been described by making use of interparticle cross-linking aggregation mechanisms; however, the data shown in this work allow for the development of new methods for detecting dsDNA in solution by using aggregated AuNPs as a starting point. The aggregation state is induced by the controlled addition of an inert electrolyte. A deconvolution procedure of the experimental plasmon shows how individual bands corresponding to aggregated nanoclusters diminish as the DNA concentration increases in the presence of 0.075 M NaCl.
众所周知，单链DNA（ssDNA）很容易吸附在柠檬酸盐包覆的、未功能化的金纳米颗粒（AuNPs）上。然而，双链DNA（dsDNA）对它们的亲和力则要有限得多。目前的工作表明，当溶液中存在阴离子纳米颗粒时，长双链DNA会发生弯曲构象变化。通过动态光散射（DLS）、粘度测定法和原子力显微镜（AFM）方法，观察到在无盐情况下双螺旋的持续长度显著降低。因此，长双链DNA被证明能够与阴离子金纳米颗粒相互作用。迄今为止，仅通过颗粒间交联聚集机制描述了单链DNA检测；然而，这项工作中展示的数据为以聚集的金纳米颗粒为起点开发检测溶液中双链DNA的新方法提供了可能。通过控制添加惰性电解质来诱导聚集状态。实验等离子体激元的去卷积过程表明，在0.075 M NaCl存在的情况下，随着DNA浓度的增加，对应于聚集纳米团簇的各个谱带如何减弱。
