Nanoparticles currently are pretty cool (they often have strong fluorescence when made with certain materials like cadmium sulfide due to weird quantum chemistry effects that go over my head), but they are essentially inert. Antibody based tests (like pregnancy tests, dip stick urine tests, and Covid tests) actually use gold nanoparticles as the indicator line. They are small enough that they scatter light in a way that makes the light appear red and are fused of antibodies that detect the presence/absence of an analyte.
People have been using them for chemotherapy as you can attach antibodies to them to target them to a tumor, and you can either blast them with microwave radiation and they get hot enough to burn tumors, or you can fuse chemo drugs to them so that you only are dosing the immediate tumor location and avoiding side effects in the rest of the body.
The issue with attempting to make nanoparticles that have recreational drugs in them is that they are far too big to get through the blood brain barrier. I have read about attempts to get them actively transported across, but I have yet to see anything promising on that front.
Nanoparticles that can compute things and actively perform functions (like nanobots popular in movies) are completely in the realm of science fiction. We already are at the limit of how small a transistor is (they are a few atoms wide), and these are already in your phones and computers. To have a functioning processor, you need either a battery or a power source, an input device, the processor itself, and a transmitter. Nanoparticles are at least a thousand times too small to fit all of this in them, and with our current ways to design circuits it currently is impossible to further miniaturize things.
What are your thoughts on this ?
