writer：Jianing Zhang, Jing Jin, Yanqiu Du, Xiang Zhou, Haojun Liang, Wei Jiang
keywords：DNA, 金纳米粒子, 稳定性, 分子机器, 盐, pH
source：期刊
specific source：Journal of Materials Chemistry B, 2019, 7(36), 5554-5562
Issue time：2019年

摘要：DNA功能化金纳米粒子（DNA-AuNPs）在构建类机器纳米器件方面展现出巨大潜力和令人兴奋的机会。非硫醇DNA可通过DNA碱基（如聚腺嘌呤polyA-DNA）接枝到金表面。polyA-DNA-AuNPs的胶体稳定性显著依赖于影响AuNPs组装及其polyA-DNA分子机器应用的盐和pH。高盐和低pH有利于稳定polyA-DNA-AuNPs。在酸性条件下，腺嘌呤可被质子化而带正电荷，通过静电和配位等多重相互作用增强polyA-DNA在金表面的吸附，实现高DNA接枝密度和胶体稳定性。此外，腺嘌呤长度对DNA机器效率有重要影响，而胸腺嘧啶长度小于等于7时影响很小。利用A5-DNA和A9-DNA成功实现了动态polyA-DNA分子机器驱动的AuNPs组装；中等浓度催化剂寡聚体（50 nM）可提高DNA杂交效率。基于A9-DNA的分子机器比A5-DNA更高效，因为AuNPs上A9-DNA数量更多，增加了互补DNA链间碰撞概率。因此，polyA-DNA功能化纳米粒子可作为基本单元构建有序组装结构，并实现应用于分子诊断领域的动态分子机器。

Abstract：DNA functionalized gold nanoparticles (DNA-AuNPs) have shown great potential and exciting opportunities for constructing machinelike nanodevices. Nonthiolated DNA can be grafted onto gold surfaces via the DNA bases, such as polyadenine (polyA)-DNA. The colloidal stability of polyA-DNA-AuNPs has a significant dependence on salt and pH that affect the assembly of AuNPs and its application in polyA-DNA molecular machine. High salt and low pH value contribute to stabilize polyA-DNA-AuNPs. In acid condition, adenine can be protonated that enables positively-charged, thus enhances the adsorption of polyA-DNA onto gold surface by electrostatic and coordination of multiple interactions to achieve a high DNA grafting density and colloidal stability. In addition, the length of adenine has an important effect on the efficiency of the DNA machine, while the length of thymine has little effect when thymine length is less or equal to seven. The assembly of AuNPs driven by dynamic polyA-DNA molecular machines is successfully accomplished with A5-DNA and A9-DNA. A moderate concentration of catalyst oligomer (50 nM) can improve DNA hybridization efficiency. A9-DNA based molecular machine is more efficient than A5-DNA because of the larger amount of A9-DNA onto AuNPs, which increases the probability of collisions between complementary DNA strands. Therefore, polyA-DNA functionalized nanoparticles can be used as a basic unit to construct assembly ordering structures and accomplish dynamic molecular machines applying in molecular diagnostics field.

论文链接：https://doi.org/10.1039/c9tb01238a