Bacteria make light work of detecting landmines

Bacteria modified to glow green in the presence of explosives could eventually provide developing countries with a cheap, easy-to-use tool for detecting landmines.

The ‘Landmine Monitor Report 2009’ of the International Campaign to Ban Landmines says there were more than 73,000 landmine casualties between 1999 and 2008. Metal detectors and trained personnel and dogs are currently used to find landmines.

Alistair Elfick, who led the research at the University of Edinburgh’s Centre for Biomedical Engineering, told SciDev.Net that his team has genetically modified Escherichia coli bacteria to produce a protein in the cell membrane that senses TNT, a chemical used in explosives.

"The novelty of our project is that previous biosensors haven’t been specific for TNT — and this chemical is a good signature for landmines," said Elfick.

The team introduced the gene for an enzyme called luciferase, which naturally produces light in some bacteria and fireflies.

When proteins on the surface of E.coli detect TNT, this "switches on" the gene responsible for light production.

The bacteria are safe to use, easily reproducible and can be dropped from aeroplanes onto potential landmine areas, says Elfick. The results are available in a few hours, whereas genetically modified plants take weeks or months.

But there are no plans to make the product commercial yet. Further testing is required and the researchers face European Union regulations regarding the use of genetically modified bacteria.

"We are only allowed to do this sort of work in our laboratories — we are not allowed to take it outside," adds Elfick. "Developing countries may have a more accepting opinion of genetically modified bacteria, so there may be less of a barrier."

Noel Mulliner, technology coordinator at the UN Mine Action Service, told SciDev.Net that he welcomes such methods but says: "There have been many attempts, none of which has proved to be sufficiently reliable to be used."

"It is one thing to get a technology to work in a laboratory or simple field test, and it is another to get it to work in the real conditions," he added.

Erik Tollefsen, technology officer at the Geneva International Centre for Humanitarian Demining, says that molecular technology may be able to complement current techniques.

"We are looking for technologies we can use to scan larger areas and detect the presence of something there, so we can go and look closer," he said.