Imagine a tiny robot - a 'nanobot' - that can swim through blood, water and air, carrying out many different tasks. Best of all, it can replicate and repair itself. We already know about nanobots like this; we call them bacteria and viruses.
|Microscope image of a T4 phage virus. It can inject its DNA into a bacterium.|
Image: Professor Hans-W. Ackermann, MD