Landmines are a hidden threat that kill and maim innocent people long after a conflict has ended. Despite the use of landmines by states now being extremely rare thanks to the 1997 Mine Ban Treaty, according the Landmine Monitor 2016, global casualties from landmines reached a 10-year high in 2015 and funding for clearance efforts reached a 10-year low. A new system that highlights the location of landmines and unexploded ordnance using glowing bacteria could help reverse this trend.

Current techniques for clearing landmines involve people physically entering minefields, which is dangerous, not to mention time and labor intensive. Last year we saw a research effort looking to speed things up and keep people out of harm's way by taking advantage of the fact that landmines leak explosive chemicals into the surrounding soil that are absorbed by foliage. It is hoped that changes in the foliage caused by the chemicals could be detected by hyperspectral imaging drones, thereby indicating a mine is buried underneath.

A new approach developed at the Hebrew University of Jerusalem takes a similar approach, but uses bacteria instead of plants to highlight the location of buried mines. Researchers genetically engineered bacteria to fluoresce under laser light when in the presence of explosive vapors seeping from the landmines. By placing these bacteria in small polymer beads and scattering them over areas suspected of harboring landmines, a laser-based scanning system can scan the area and detect the location of landmines buried beneath the surface.

The team trialed the system on a test field in which real antipersonnel landmines were buried. In what the researchers believe is the first successful demonstration of a functional standoff landmine detection system, they were able to remotely scan the field and determine the location of the mines. However, work still needs to be done to make the technology practical.

"Our field data show that engineered biosensors may be useful in a landmine detection system," says Prof. Shimshon Belkin, who genetically engineered the bacteria. "For this to be possible, several challenges need to be overcome, such as enhancing the sensitivity and stability of the sensor bacteria, improving scanning speeds to cover large areas, and making the scanning apparatus more compact so it can be used on board a light unmanned aircraft or drone."

The team's research appears in the journal Nature Biotechnology.

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