Molecular Threading: Mechanical Extraction, Stretching and Placement of DNA Molecules from a Liquid-Air Interface

We present “molecular threading”, a surface independent tip-based method for stretching and depositing single and double-stranded DNA molecules. DNA is stretched into air at a liquid-air interface, and can be subsequently deposited onto a dry substrate isolated from solution. The design of an apparatus used for molecular threading is presented, and fluorescence and electron microscopies are used to characterize the angular distribution, straightness, and reproducibility of stretched DNA deposited in arrays onto elastomeric surfaces and thin membranes. Molecular threading demonstrates high straightness and uniformity over length scales from nanometers to micrometers, and represents an alternative to existing DNA deposition and linearization methods. These results point towards scalable and high-throughput precision manipulation of single-molecule polymers.

本文报道分子穿引法（molecular threading），这是一种不依赖基底、基于尖端探针的单链及双链脱氧核糖核酸（DNA）分子拉伸与沉积技术。DNA分子可在气液界面处被拉伸至空气中，随后可沉积至与溶液隔离的干燥基底之上。本文同时介绍了该方法所用实验装置的设计方案，并通过荧光显微镜与电子显微镜，对以阵列形式沉积于弹性体表面及薄膜上的拉伸DNA分子的角度分布、平直度与重现性进行了表征。分子穿引法在纳米至微米级尺度范围内展现出优异的平直度与均匀性，可作为现有DNA沉积与线性化技术的替代方案。上述研究成果为单分子聚合物的规模化、高通量精准操控提供了可行的发展路径。