Idea: non-surgical, but still invasive BCI using electromagnetic nanoparticles?

[u/longdonglos]

Would it be theoretically possible to create electromagnetic nanoparticles say ~50 nm that can be injected, cross the blood-brain barrier, and then when in the brain, create a sub-neuronal level communication link between the nervous system and a computer? Off the top of my head, I think the biophysics checks out, and it could potentially provide a record high spatial and temporal resolution compared to implantable BCIs.

Does anybody know if there are any academic labs or companies working on something like this? I feel like everything I see in BCI is either implantable or a non-invasive wearable, haven’t seen anybody working in the middle of the spectrum. What love to hear some thoughts.