Land mines are the scourge of the survivor. They lurk in the soil for years and even generations after the fighting ends.
Up to 20,000 people a year are wounded or killed after stumbling on hidden mines, and there has been no safe way for man or beast to detect them.
Until now: Scientists at the Hebrew University of Jerusalem have developed a novel mine-detection technique using bacteria, which nobody cares about, and lasers, ditto. The concept has passed its feasibility test, though some work remains necessary before it can be commercialized.
Mine detection techniques have remained as pedestrian as they were in World War II: soldiers with sticks and serendipity; dogs, who do get killed; and pigs (a talent discovered by a kibbutznik in Israel). The most noteworthy advance in decades had been recognizing the mine-sniffing talents of the African pouched rat.
There is no shortage of the explosive devices for these animal detectives to discover, which they do by recognizing the odor of the explosives inside them.
According to Hebrew University, more than 100 million land mines remain buried around the world. Metal detectors do fine with traditional mines, but plastic ones elude them.
The solution concocted at Hebrew University, which the scientists have published in the journal Nature Biotechnology, is based on the long-known fact that all mines leak explosive vapors that accumulate in the surrounding soil. If you can detect that toxic gas, you have found a mine.
Inspired by an idea that was first conceptualized in 1999, the scientists engineered bacteria that fluoresce when they come into contact with these vapors.
The human mine detectors don’t have to keep the bacteria on a leash: they can monitor and react remotely. Nor are the bacteria free-range: they are encapsulated in beads that are scattered across the suspect land.
The scientists tested the system with a laser-based scanning system, and the mines were found.
“This appears to be the first demonstration of a functional standoff land mine detection system,” the university said in a statement.
Some improvements remain to be done, the scientists admit: They have to enhance the sensitivity and stability of the sensor bacteria, to improve scanning speeds in order to cover large areas and to miniaturize the scanning apparatus so that, for example, it could be installed on a drone, says Prof. Shimshon Belkin, who was responsible for genetically engineering the bacterial sensors.