金纳米粒子-DNA折纸组装体的构建及对17β-雌二醇的检测

Construction of gold nanoparticle-DNA origami assemblies and application for detecting 17β-estradiol

中文关键词:  DNA折纸  自组装  金纳米粒子  球形核酸

英文关键词:DNA origami  self-assembly  gold nanoparticals  spherical nucleic acids

中文摘要:

      目的 建立“一步退火”法实现金纳米粒子在DNA折纸上的高效组装, 结合适配体, 采用原子力显微镜(atomic force microscope, AFM)实现17β-雌二醇(17β-estradiol, E2)的可视化检测。方法 巯基修饰的DNA和金纳米粒子混合物(SH-DNA/gold nanoparticals, SH-DNA/AuNPs)与正丁醇接触, 快速除去水分, 通过Au-S键共价结合形成致密的球形核酸(spherical nucleic acids, SNAs)。引入一种自下而上可编程DNA自组装的方法-DNA折纸术, 利用其精确的定位功能, 将DNA折纸单链和球形核酸混合, 一步退火形成DNA折纸-金纳米粒子组装体结构。进一步将DNA折纸与适配体结合, 金纳米粒子作为信号探针, 利用AFM进行E2的可视化检测。结果 通过加盐实验和电位表征, 表明正丁醇法能够在几秒内完成金纳米粒子的表面功能化, 节省了实验时间; 通过AFM表征, 表明“一步退火”可以实现金纳米粒子在DNA折纸上的高效组装, 并且“一步退火”的组装效果远远好于“二步退火”。生物传感器可以通过AFM直观地检测50 ng/mL的E2。结论 本研究利用正丁醇法合成的球形核酸经过一步退火实现了在DNA折纸上的高效组装, 同时提出了基于DNA折纸可视化检测E2的纳米生物传感新方法。

英文摘要:

      Objective To establish a “one-step annealing” method to achieve efficient assembly of gold nanoparticles on DNA origami, and realize visually detection of 17β-estradiol (E2) with atomic force microscope (AFM) combined with aptamers. Methods Dense spherical nucleic acids (SNAs) were realized by a rapid water removal from SH-DNA/gold nanoparticals (SH-DNA/AuNPs) mixtures in contact with a butanol phase and covalently bind by the Au-S bond. DNA origami, a bottom-up programmable DNA self-assembly method was introduced, using its function of precise localization, single strands of DNA origami and SNAs were mixed, and the DNA origami-gold nanoparticle assembly structure was formed in one step annealing. Further, DNA origami was combined with aptamer, and gold nanoparticles were used as signal probes, which were analyzed by AFM to realize visual detection of E2. Results The salting experiment and zata potential characterizations showed that the method of using n-butanol could realize the surface functionalization of gold nanoparticles in a few seconds, which greatly saved the experimental time. AFM characterization indicated that the “one-step annealing” could finish the efficient assembly of gold nanoparticles on DNA origami, and the assembly effect of “one-step annealing” was much better than that of “two-step annealing”. The biosensor could intuitively detect 17β-estradiol at 50 ng/mL via AFM. Conclusion In this study, the SNAs synthesized by the n-butanol method have been efficiently assembled on DNA origami through one-step annealing, and a new DNA origami based nanobiological sensing method to visually detect 17β-estradiol has been proposed.