Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
J Am Chem Soc. 2012 Jan 11;134(1):35-8. doi: 10.1021/ja207661z. Epub 2011 Dec 19.
The melting temperature (T(m)) of DNA is affected not only by salt but also by the presence of high molecular weight (MW) solutes, such as polyethylene glycol (PEG), acting as a crowding agent. For short DNAs in a solution of low MW PEGs, however, the change of excluded volume upon melting is very small, leading to no increase in T(m). We demonstrate herein that by attaching 12-mer DNAs to gold nanoparticles, the excluded volume change was significantly increased upon melting, leading to increased T(m) even with PEG 200. Larger AuNPs, higher MW PEGs, and higher PEG concentrations show even larger effects in stabilizing the DNA. This study reveals a unique and fundamental feature at nanoscale due to geometric effects. It also suggests that weak interactions can be stabilized by a combination of polyvalent binding and the enhanced macromolecular crowding effect using nanoparticles.
DNA 的熔解温度 (T(m)) 不仅受盐的影响，还受高分子量 (MW) 溶质的存在影响，如聚乙二醇 (PEG)，作为一种拥挤剂。然而，对于低 MW PEG 溶液中的短 DNA，熔解时排除体积的变化非常小，导致 T(m) 没有增加。本文中，我们证明通过将 12 -mer DNA 连接到金纳米粒子上，熔解时排除体积的变化显著增加，即使使用 PEG 200 也能增加 T(m)。更大的 AuNPs、更高 MW 的 PEG 和更高的 PEG 浓度对稳定 DNA 的效果更大。这项研究揭示了由于几何效应而在纳米尺度上的独特和基本特征。它还表明，弱相互作用可以通过多价结合和使用纳米粒子增强的大分子拥挤效应的组合来稳定。
