A molecular device for the detection of aqueous environmental pollution

A project undertaken at The Institute for Biomedical Research, The University of Sydney, and supervised by C dos Remedios

Assessment of the toxicity of waste water is a major global problem. There exists a wide range of biological tests and chemical analyses that are used in the laboratories of organisations around the world such as environmental protection agencies. All of these tests are expensive. All require substantial investments in infrastructure. All require human resources and time. And none of the existing tests can evaluate biotoxicity in both fresh and salt water.

The objective of the project was to build a quantitative or semi-quantitative test that was based on biological macromolecules because they were the ones affected by exposure to toxicants. The test was required to be as sensitive as the biological testing methods currently in use. The system would also need to work in fresh water and would be only minimally (<20%) affected by salt water. It was hoped that the testing equipment developed would be portable, cheap and fast.

The result is the development of a DNA-based assay capable of sensing heavy metals like mercury ions with micromolar sensitivity and, like its equivalent tests, is able to respond to a range of heavy metal ions. This DNA-based system is as good as any of its competitors and will take its place in the battery of tests that will help to pinpoint sources of toxicants at a minimum of cost.

Patent Position  Today we have an International patent (dos Remedios, C.G., Cooke, A.R. and M. Kekic (2001) International Patent PCT/AU01/00099 "Biomolecular toxicity assay"), we have proof of concept for the use of biological macromolecules (protein-protein interactions and the binding of fluorescent ligands to DNA), and we have a working prototype that is portable and provides an evaluation of the biotoxicity of an aqueous sample within seconds.

We intend to continue the development of our biotoxicity test by reducing the size or the equipment and improving its ability to monitor environmental pollution. Over the next 12 months, we are also likely to develop a YES/NO test that does not require a measuring instrument.

Returning the Capital Investment  The commercial vehicle developed to take this test forward (HazardScreen Pty Ltd) intends to develop and enhance the IP so that it can return funds to the Foundation for the benefit of future projects that improve the quality of life in Australia and elsewhere.

Molecular basis of the DNA-based assay.

Prototype test equipment.