Remote Bio-Detection of Buried Landmines by Luminescent Microbial Sensors ^†

Landmines and explosive remnants of war pose a global humanitarian problem and cause numerous casualties long after the conflict has ended. The current approaches for locating landmines, such as metal detection, which require one’s physical presence at the minefield, involve high risk to personnel; these methods are also costly, time-consuming, and have a high rate of false-positive results. There is no currently viable technology for the remote detection of buried explosive devices. A possible solution to this may be the use of genetically engineered microorganisms, molecularly “tailored” to emit an optical signal in the presence of trace explosives escaping for the landmine and accumulating in the soil above it. This optical signal, imaged from a remote location, can then be used to generate a physical map of the mine’s location. A few years ago, we have described the remote detection of buried landmines using alginate-encapsulated fluorescent microbial (Escherichia coli) bioreporters spread over the tested minefield. Since then, we have modified the system to one based on bioluminescent (rather than fluorescent) bacteria and have employed several synthetic biology approaches to significantly enhance their major performance parameters: higher signal intensity, faster response time, and lower detection threshold of the target explosives. These molecular approaches and their effect on sensor performance will be described.