So, they seem to have made special DNA probes that attaches to some cancer-specific bit of RNA, and the combination of the two stuck together is something they can detect via "scanning tunneling microscopy break junction (STM-BJ)". Is that right?

I guess the question is whether you can use this DNA/RNA detection method without having a whole sophisticated STM setup as the other part of the detector. The article says calls it a nanobiosensor, and says it "has a promising future as an inexpensive, highly sensitive and label-free miniaturized device for early-stage cancer screening of liquid biopsies".

This is really cool, but it's only a nanobiosensor insomuch as you can get a useful signal out of it without an expensive scanning tunneling microscope setup attached, I would assume!