Department of Mechanical & Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
Nanoscale. 2018 Dec 20;11(1):34-44. doi: 10.1039/c8nr08421a.
Solution-phase self-assembly of DNA-functionalized nanoparticles into mesoscale structures is a promising strategy for creating functional materials from nanocrystal building blocks. The predominant approach has been the use of Watson-Crick base pairing between complementary bases in designated 'sticky ends' to trigger programmable self-assembly into ordered superlattices. Here we demonstrate the ordered self-assembly of Au nanoparticles conjugated with single-stranded (ss) DNA in acidic solutions. Au nanoparticles functionalized with thiolated ssDNA are protected against coalescence and the DNA conformation undergoes significant modifications at low pH, which can be associated with the protonation of adenine bases and the formation of a parallel poly-adenine duplex, which govern the interaction between ssDNA-Au nanoparticle conjugates. In situ liquid cell electron microscopy enables real-time imaging of the self-assembly process and the identification of key characteristics, such as the preferred structural motifs and interparticle separations in the native solution environment. Our results highlight alternatives to conventional base-pairing interactions for building DNA-directed nanoparticle superlattices.
DNA 功能化纳米颗粒在溶液相中自组装成介观结构，是一种很有前途的策略，可以用纳米晶构筑块来制造功能材料。主要方法是利用指定的“粘性末端”中互补碱基之间的沃森-克里克碱基配对来触发可编程的自组装成有序超晶格。在这里，我们展示了在酸性溶液中通过单链 DNA 连接的金纳米颗粒的有序自组装。巯基化的单链 DNA 功能化的 Au 纳米颗粒可以防止聚集，并且在低 pH 值下 DNA 构象发生显著变化，这可能与腺嘌呤碱基的质子化和形成平行的多腺嘌呤双链体有关，后者控制着 ssDNA-Au 纳米颗粒缀合物之间的相互作用。原位液体池电子显微镜能够实时成像自组装过程，并识别关键特征，如在原始溶液环境中的优先结构基元和颗粒间分离。我们的结果强调了用于构建 DNA 导向的纳米颗粒超晶格的替代传统碱基配对相互作用。
