If you weigh a handful of coins of the same denomination but different minting, you will learn only the average weight. But if you sort them by shape, you can see which coin bends more easily. The same goes for DNA: in solution it can adopt several shapes with the same mass, and the usual method saw only the average. The new approach adds sorting by shape, and now each shape can be studied on its own.
Using this method, scientists saw that one DNA shape unfolds three times faster than another. This matters because such structures can be targets for cancer drugs, and you need to know which shape is more stable. Now drugs can be tested more precisely, without the risk that the result will be spoiled by an admixture of another shape.
Guanine quadruplexes can form structures reminiscent of a stack of pancakes: flat guanine tetrads pile on top of one another, and potassium ions sit between them like filling.
The idea of separating molecules by shape in the gas phase is reminiscent of a fictional "sorter" from a Philip K. Dick story, where objects are classified by nonobvious features. Only here, instead of a fantastic device, there is a drift tube filled with helium.
Not published on arXiv. Here are its page, the PDF and the formalization: you can check it yourself, not only read our account.