The breakthrough is reported in today's edition of the international scientific journal Nature by a team from the Co-operative Research Centre for Molecular Engineering and Technology (CRC-MET). CRC-MET is a joint venture of the CSIRO, the University of Sydney and the Australian Membrane and Biotechnology Research Institute.

The device is a biosensor -- a combination of biology and physics, designed to detect substances with extreme sensitivity. Its central component is a tiny electrical switch, an ion-channel, 1.5 billionths of a metre in size.

The device was created by Dr Bruce Cornell of CSIRO and his colleagues. Their work was largely funded by the Australian Government through the Industrial Research and Development Board (IRDB) and Co-operative Research Centres scheme. Substantial commercial support has been provided by a Pacific Dunlop Limited subsidiary, AMBRI Pty. Ltd. through the Research Institute.

"This biosensor is a unique blend of the ability of biology to identify individual types of molecule in complex mixtures, with the speed, convenience and low cost of microelectronics, " Dr Cornell says.

"It consists of a synthetic membrane that we make ourselves, chemically tethered to a thin metal film coated onto a piece of plastic. This membrane behaves like the outer skin of the cells of the human body in its ability to sense other molecules.

"As we evolved from the sea, it is not surprising that ions (single atoms) in sea water such as sodium and potassium play a role in human cell signalling and sensory systems. These depend on ion currents that flow across certain cell membranes.

"When the membrane detects its target molecule, it turns these currents on or off by opening or closing molecular channels that pass through the otherwise insulating membrane.

"We have made a synthetic version of this mechanism that is stable, inexpensive and convenient to use as a molecular detector. Being a biological mimic it even operates successfully in whole blood.

"We have demonstrated a sensitivity 1,000 times better than previous biosensors while the direct electrical rather than the usual optical output ensures compatibility with microelectronics. This allows us to produce a very simple, quantitative, readout."

AMBRI's Keith Daniel says biosensors have a huge range of potential uses, especially in medicine, for detecting drugs, hormones, viruses, pesticides and to identify gene sequences for diagnosing genetic disorders.

In the pharmaceuticals industry the device may also be used to screen for potential new drugs and medically-active compounds.

"Because of their low cost, very high sensitivity and ease of use, they will also find particular application in on-site measurements, such as ensuring food safety and quality, in environmental monitoring and drug detection in athletes" he says.

Dr Cornell describes the biosensor's sub-picomolar sensitivity as equivalent to detecting the increase of the sugar content of Sydney Harbour after throwing a sugar cube from a ferry.

"We are designing them to be very simple to operate. We've even had corporate lawyers assembling and working them.

"It has taken us nine years to bring the device from first concept to the present stage," he says.

"Without the support and trust of many people from both Government and Australian industry this project would not have survived.

"We now have a chance to be in at the start of a new generation of technologies, such as our biosensor; devices which operate on the molecular or nanometre scale. We need to take full scientific and commercial advantage of this early lead."

The team's biosensor has been operating successfully for several months in the laboratory and the first commercial products are expected to be launched within two years.

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Reference: B.A. Cornell, et. al. "A biosensor that uses ion channel switches" Nature, Vol 387, June 5, 1997; pp. 580-583. Supplementary information is on Nature's Web Site at www.Nature.com

More detailed technical and other information including some good pictures are available at http://www.ambri.com.au/index_real.html while under the above embargo. A browser capable of displaying "Frames" is required.

After the embargo this information is available on http://www.ambri.com.au

Media Contact: Mr Keith Daniel, AMBRIB
+61 2 9422 3003 (office & mobile)
+61 2 9422 3013 (Facsimile)

Dr Bruce Cornell, CSIRO
+61 2 9422 3195 (office & mobile)

Note: The terms Nanomachine and Nanotechnology come from the Greek word nanos. They refer to devices whose parts can be measured in nanometres, or billionths of a metre.

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