It has, though, taken Dr Baselt and his colleagues, along with researchers in several other organisations, ten years to turn his insight into a practical technology.

ECONOMIST: Labs on a chip

In 1998, however, it occurred to David Baselt of the United States' Naval Research Laboratory in Washington, DC, that spin valves might also make excellent biosensors.

ECONOMIST: Labs on a chip

To Dr Baselt this suggested that tiny magnetic particles might be attached to molecules using either antibodies (which will bond to proteins, sugars and so on) or single-stranded DNA (which will bond to a complementary DNA strand to form the famous double helix).

ECONOMIST: Labs on a chip