Department of Physics, New York University, New York, NY, USA.
Courant Institute of Mathematical Sciences, New York University, New York, NY, USA.
Nat Commun. 2022 Apr 28;13(1):2304. doi: 10.1038/s41467-022-29853-w.
The self-assembly of DNA-coated colloids into highly-ordered structures offers great promise for advanced optical materials. However, control of disorder, defects, melting, and crystal growth is hindered by the lack of a microscopic understanding of DNA-mediated colloidal interactions. Here we use total internal reflection microscopy to measure in situ the interaction potential between DNA-coated colloids with nanometer resolution and the macroscopic melting behavior. The range and strength of the interaction are measured and linked to key material design parameters, including DNA sequence, polymer length, grafting density, and complementary fraction. We present a first-principles model that screens and combines existing theories into one coherent framework and quantitatively reproduces our experimental data without fitting parameters over a wide range of DNA ligand designs. Our theory identifies a subtle competition between DNA binding and steric repulsion and accurately predicts adhesion and melting at a molecular level. Combining experimental and theoretical results, our work provides a quantitative and predictive approach for guiding material design with DNA-nanotechnology and can be further extended to a diversity of colloidal and biological systems.
DNA 包覆胶体的自组装为先进光学材料提供了广阔的前景。然而，由于缺乏对 DNA 介导胶体相互作用的微观理解，对无序、缺陷、熔融和晶体生长的控制受到阻碍。在这里，我们使用全内反射显微镜以纳米分辨率原位测量 DNA 包覆胶体之间的相互作用势和宏观熔融行为。我们测量了相互作用的范围和强度，并将其与关键的材料设计参数联系起来，包括 DNA 序列、聚合物长度、接枝密度和互补分数。我们提出了一个第一性原理模型，将现有的理论筛选并组合到一个连贯的框架中，并在广泛的 DNA 配体设计范围内无需拟合参数就能定量重现我们的实验数据。我们的理论确定了 DNA 结合和空间排斥之间的微妙竞争，并在分子水平上准确预测了粘附和熔融。结合实验和理论结果，我们的工作为指导 DNA-纳米技术的材料设计提供了一种定量和预测方法，并可进一步扩展到多种胶体和生物系统。
