The morphology of DNA solution in an open fluidic channel studied by non-contact AFM

The morphologies of pure buffer solution and DNA-containing solution in an open fluidic channel with rectangle cross section (1 μm in width and 150 nm in depth) have been explored using non-contact AFM. A remarkable feature is that a uniform nano-scale trench (∼15 nm deep and 14 μm long) on the surface of the DNA solution has been observed. The presence of two neighboring stretched DNA molecules near the solution surface may be responsible for the configuration of the nanotrench. This new phenomenon of partially stretched DNA molecules is likely to be useful for the future designing of fluidic devices, and for the manipulation and study of single DNA molecules.