Published by Australian Academy of Science
Nanoscience – working small, thinking big Box 3 | In nature's footsteps

One day our science might match nature in its ability to self-assemble wonderful structures that possess incredible properties. However, until that day, why not borrow from nature's library of success stories to build our own nano-devices? That's just how the Australian biosensor, one of the world's first nanomachines, came to be. This biosensor can detect vanishingly small concentrations of a substance. Its sensitivity is such that it could detect whether a sugar cube had been added to Sydney Harbour!

The biosensor is an amalgam of biological structures. First, it detects the substance being searched for with an antibody, just like in our immune systems. The antibody is connected to an ion channel switch which is contained within a membrane anchored to a gold electrode. When the antibody latches onto the substance being detected, an electrical current can be measured at the gold electrode. This approach promises a revolution in accurate, sensitive and inexpensive chemical detection. For example it could be used to detect environmental pollutants or bacteria used as biological weapons.

Approaches like this may one day have an armoury of sensors testing for all sorts of things on a tab the size of an icy pole stick. A drop of your blood or saliva might be placed on this tab and in moments you would be tested for a whole range of diseases and disorders. It really would be a revolution in diagnosis.

Related sites

• Critters on a chip (Scientific American Explorations)

• An introduction to the Ambri biosensor (Ambri Ltd, Australia)

• Australia considers threat of biological warfare (transcript of Lateline, 3 October 2001, Australian Broacasting Corporation)

• A biosensor that uses ion-channel switches (letters to Nature 5 June 1997)

Other boxes

Box 1. Room at the bottom

Box 2. Nanomanipulation