Proof of concept for detecting buried landmines by bacterial chemical sensing

We describe a first demonstration of detecting “live” antipersonnel landmines buried outdoors by an optoelectronic bacterial chemical sensor. Over 150 million such landmines, leftovers from past wars, are buried across huge areas worldwide, constituting a tremendous humanitarian and economic world problem. A prior condition for their deactivation is to detect their locations. Currently, there is no viable technology to do so. The detection method presented herein exploits the fact that buried landmines release a material that permeates to the surface of the ground, generating a chemical signature above the landmine location. The method is implemented by the biosensing module (BSM) which employs bioluminescent sensing bacteria (bioreporters). These were genetically engineered to respond to the presence of the said chemical signature by producing bioluminescence. They were then loaded in the BSM, encased in polymeric capsules together with water and nutrients, and served as the BSM sensing devices. The BSM was tested for detecting TNT landmines which constitute 90% of the landmines buried worldwide. The TNT in the landmines secretes the volatile material DNT that forms its chemical signature. In laboratory experiments, DNT traces were detected in soil containing ≈50 ppb of DNT under the BSM footprint. We report herein that BSM units deployed in a “live” minefield, detected the chemical signature produced by buried antipersonnel TNT landmines. We argue that these measurements provide a proof of concept for the BSM ability to detect buried TNT landmines, and motivates the BSM network as the system for detecting landmines across wide areas.