Gene-Tweaked Mice Tailored to Sniff Out TNT
An unexploded ordnance site being cleared by metal detectors in Laos.
CREDIT: UXO Lao
The pitter-patter of tiny feet could announce the arrival of tomorrow's landmine detectors — lab mice genetically engineered by humans to sniff out TNT explosives.
The idea became reality in a New York City lab that already created and bred the special breed of mice. Such mice have a sense of smell 500 times better than normal at detecting DNT, a chemical cousin of TNT, and they may alert humans to the presence of landmines by possibly falling down in an epileptic seizure.
"Whatever their behavior is going to be, we think we will be able to track their change in behavior using a sort of microchip implanted under their skin that would indeed wirelessly report back to a computer," said Charlotte D'Hulst, a bioengineer at Hunter College, City University of New York.
The mice could go a long way toward saving human lives in a world where landmines kill 15,000 to 20,000 people every year, according to the United Nations. A Belgian nonprofit has already trained giant African pouched rats to sniff out landmine explosives in a matter of hours compared with days for humans using metal detectors.
But the rats require nine months of training based on banana food rewards. The genetically modified mice could prove faster to breed and would require much shorter training, D'Hulst said. She presented her research at the Neuroscience 2012 conference in New Orleans on Oct. 14.
"The major advantage of the approach is that we will have created animals with an inherent super sensitivity to DNT, which will make the training significantly quicker," D'Hulst told TechNewsDaily. "Mice are smaller, cheaper and very easy to breed in large numbers, so one could get more animals do the job simultaneously (about 500, for example)."
Recent research suggests the mice may fall down and undergo epileptic seizures in response to the smell of TNT — the result of all the sensory neurons firing off in their hypersensitive noses and flooding the brain with signals. But whatever their response, researchers anticipate using the implanted microchips implanted microchips to detect whether the mice had found explosive material.
D'Hulst and her colleagues — lead by Paul Feinstein, a neurogeneticist at Hunter College, City University of New York — still need to test how the mice react to DNT in the lab and on the field. But she expects that the mice could be ready for action in five years if all goes well. [Genetically Engineered Cell Shoots Out First-Ever Biological Laser]
The MouSensor Project, funded by the National Institutes of Health, could also eventually lead to mice genetically modified with special noses for other jobs — sniffing out tuberculosis in humans, identifying contaminated water, or perhaps helping rescue workers locate survivors of natural disasters.
Researchers created the special mice for the landmine detection job by injecting genetically modified DNA into a fertilized mouse egg, so that the embryos could be surgically implanted in a female mouse. The female mice were tricked into becoming "pseudopregant" by mating them with male mice who had undergone vasectomies to prevent them from breeding.
"Whether or not genetically engineered mice should be used for the sake of land mine detection is indeed an ethical question," D'Hulst said. "However, we still have to investigate the behavioral outcome of DNT exposure to our DNT MouSensors, so I think it's still too early to start this discussion."
Luckily for both mice and men, the tiny mice are too small to set off any landmines on their own if they end up on future and former battlefields.