Neat idea. I wonder how much this differs from the more commonly used method of employing hydrodynamic flow to stretch DNA (e.g. in DNA curtains).
One additional note:
If you look at an image of a DNA molecule in solution or in the cell, two genes that are very far apart along the molecule could appear very close in the image, and not much can be learned from looking at how the molecule is organized.
While I agree with this is true for a DNA molecule in solution, this is definitely not true for DNA in a cell. Biologists are very interested in studying the three dimensional architecture of the genome inside of the cell and how this architecture changes during cell differentiation (scientists have dubbed efforts to study these questions as the "4D nucleome project"). Imaging different regions of DNA to look at some of the scaling laws governing their folding inside of the cell has revealed some interesting polymer physics: https://www.nature.com/articles/nature16496