On 29Apr2018 1706, Robert O'Connor wrote:

> You raise another problem with nanotech: how do the tiny robots
> 'self-direct'?
>
> Chemical or temperature gradients?
> Recognition of (cell and tissue) surface molecules?
>
> They are too small (micrometre and smaller scale) to have
> electromagnetic or sound-based sensors.

Sounds to me like these 'tiny robots' might as well be the shells of a
large virus, tailored for the target cells, and the DNA/RNA and proteins
normally found within removed and the desired drug added. The problem
being that in the quantities needed to have a rapid effect the victim's
body would almost certainly notice the viral shells and react strongly.
Anaphylactic shock is probably not what one was looking for.

--
Rupert Boleyn <xxxxxx@gmail.com>
Chief Assistant to the Assistant Chief