Michael Pycraft Hughes: Tiny things will change the world

From a speech by the lecturer in microengineering to the British Association of Science in Manchester

If engineering is the solving of problems, then microengineering is solving of problems on the scale of the micrometre - one millionth of a metre long. Most of us are familiar with the results of microengineering in the form of silicon chips, the electronic devices that power computers. But we can also apply microengineering principles to medicine and biology - working at the size of the cells of which the body is made.

Nerve cells have limited ability to repair themselves when damaged. This can lead to permanent damage, as exemplified by the actor Christopher Reeve, who has been paralysed as a result of a broken spinal cord. By implanting miniature computers that analyse the outside world and the way in which the implantee interacts with it, it is possible to restore some of the abilities lost as a result of damage elsewhere in the body: for example, stimulators implanted into the ear - directly interfacing with the nerves - have enabled the deaf to hear.

But why stop there? The next generation of technology will explore the next size down from the micrometre - the nanometre, a thousand times smaller still. There is already speculation about nano-scale robots being injected into the bloodstream and entering cells, repairing damaged DNA to prevent cancer before it starts. While such flights of fancy owe more to the 1960s science-fiction film The Fantastic Voyage than to actual science, it is possible to imagine devices the size of cells doing simple jobs such as scouring away cholesterol from the inside of blood vessels.

Ultimately, whether such devices enter the armoury of conventional medicine is far more likely to depend on the cost as much as on the feasibility of building them.