On the molecular scale, you find it's reasonable to have a machine that does a million steps per second, a mechanical system that works at computer speeds.

The really big difference is that what you make with a molecular machine can be completely precise, down to the tiniest degree of detail that can exist in the world.

You can find academic and industrial groups doing some relevant work, but there isn't a focus on building complex molecular systems. In that respect, Japan is first, Europe is second, and we're third.

Protein engineering is a technology of molecular machines - of molecular machines that are part of replicators - and so it comes from an area that already raises some of the issues that nanotechnology will raise.

I had been impressed by the fact that biological systems were based on molecular machines and that we were learning to design and build these sorts of things.

But while doing that I'd been following a variety of fields in science and technology, including the work in molecular biology, genetic engineering, and so forth.