eli5 How do scientists make microscopic machines and nano bots?


For example I just saw an image from an electron microscope that showed a nano injector used to inject dna into a single cell.

And the machine looked highly engineered and obviously man-made with crisp and elegant structures. But it is small as heck. It’s insane

In: 3

It seems that they use a chemical that eats stuff when exposed to light, then put it in a dark box with a projector to “sculpt” it.

These are MEMS devices – micro electro-mechanical systems. They are primarily made via photolithography which is the set of techniques we use to make computer chips. This is why we are so good at it; we have had a lot of practice.

The technique is both additive and subtractive. You start with a wafer of silicon, and use light and a mask (like a stencil for spray painting) to alter the properties of part of the surface. This allows you to then use chemicals to selectively etch away part of the material. You can also selectively build up more material in specific places, basically by using a mask again to make parts of the surface “sticky” so that new material will bond only there. You can also etch by bombarding the wafer with energetic particles, anything from electrons to heavy ions (the nuclei of heavy elements). You do these steps repeatedly and so build up the structures you can see in this image.