Planning on using off-the-shelf probes in your AFM? How cheap can you get those nowadays? I remember being worried about crashing them too often with our modest lab budget.

No, I'll be manufacturing them. There are alternative ways of making cantilevers with atomically-sharp tips. Tungsten wire, for instance, can be etched down to less than a few nanometers. And the quartz clocks in almost all electronic devices can be decapped and used as an oscillator.

> I've recently started designing a really cheap atomic force microscope, which I plan to open-source, so I think that may be a valuable addition to the bio and nanotech diy community.

I hope you do

Thank you, hopefully external validation will push me to actually complete the project.

AFM isn't really used in biology.

But it is used a lot in biophysics!

It is? I mean, that was my PhD, but I don't recall anybody ever using AFM for biology. Huh, apparently now they do.

Yeah lots of single molecule studies (strength of an actin filament, how much force needed to 'unfold' various proteins, etc). And this was 20 years ago when I was in grad school. Haven't kept up with the state of the art today.

interesting. all the people doing that in my day (also 20 years ago) used fluorescent microscopes (Ron Vale) with labelled protein. I can't see how you could unfold a protein using AFM, since it's in vacuum state, although I totally understand how optical tweezers would be fine to do this in solution.

AFMs work in both air and fluid environments.