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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

by tux3 3y ago

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!

haldujai 3y ago
Basically. It's been a while since I've worked in wetlabs (clinical now) but looking at their methodology the fixed equipment costs would seem comparable to ddPCR and I'd expect cheaper than NGS currently used for ctDNA. Per-unit consumable costs also seem negligible. The specific AFM setup they used here is pretty old and can be replicated (relatively) inexpensively. I would guess the biggest cost barrier/disadvantage would be throughput rather than setup costs but these results appear to be a potentially good and/or cost-effective solution to the sensitivity issues.
camus_absurd 3y ago
I think you’re overestimating the complexity of an stm setup. There exist small coffee machine sized stm machines because the principal behind the operation is relatively straightforward. People have made diy stm machines using piezo electric buzzers as the component that moves a tungsten needle over a sample. It’s relatively easy to make atomically thick tungsten needle points because of how it fractures along its grain structure. The tech behind the principle of operation of an stm is already ubiquitous.

by tux3 3y ago

haldujai 3y ago

Basically. It's been a while since I've worked in wetlabs (clinical now) but looking at their methodology the fixed equipment costs would seem comparable to ddPCR and I'd expect cheaper than NGS currently used for ctDNA. Per-unit consumable costs also seem negligible. The specific AFM setup they used here is pretty old and can be replicated (relatively) inexpensively. I would guess the biggest cost barrier/disadvantage would be throughput rather than setup costs but these results appear to be a potentially good and/or cost-effective solution to the sensitivity issues.

camus_absurd 3y ago

I think you’re overestimating the complexity of an stm setup. There exist small coffee machine sized stm machines because the principal behind the operation is relatively straightforward. People have made diy stm machines using piezo electric buzzers as the component that moves a tungsten needle over a sample. It’s relatively easy to make atomically thick tungsten needle points because of how it fractures along its grain structure. The tech behind the principle of operation of an stm is already ubiquitous.