Toward nanorobots that swim through blood to deliver drugs [video]

I remember giving a presentation on nanotechnology about 7 years ago as a freshman in high school, and this implementation was one of the 'fantasy' use cases I covered. 7 years seems like a lifetime ago, yet so short when discussing the development of world-changing technology like this. It is a truly exciting time we live in.

" And when they applied an oscillating magnetic field, the nanoswimmer moved in an S-like, undulatory motion at the speed of nearly one body length per second. "

If applying an external magnetic field, why not just use that to direct the drug delivery?

Why not just use biology (eg antibodies) to direct the drug delivery?

It is being done https://en.wikipedia.org/wiki/Monoclonal_antibody_therapy

Often these drugs are very expensive, and the targeting is to a specific receptor rather than a specific region.

A magnetically or swim steered drug delivery would be for targeting a specific region/ location in the body, or perhaps to move into areas that are hard or slow to move into with simple diffusion.

Stupid question: how come they avoid white blood cells?

White blood cells might destroy them.

this has been fantasized in metal gear solid for so long now...