Locusts engineered as biorobotic sensing machines

A plague of bomb-sniffing cyborg locusts could replace dogs
July 11, 2016

Sensors placed on the insect monitor neural activity while they are freely moving, decoding the odorants present in their environment. (credit: Baranidharan Raman)

Washington University in St. Louis engineers have developed an innovatiave “bio-hybrid nose” that could be used in homeland security applications, such as detecting explosives, replacing state-of-the-art miniaturized chemical sensing devices limited to a handful of sensors.

Compare that to the locust antenna (where their chemical sensors are located): “it has several hundreds of thousands of sensors and of a variety of types,” says Baranidharan Raman, associate professor of biomedical engineering, who has received a three-year, $750,000 grant from the Office of Naval Research (ONR).

The team previously found that locusts can correctly identify a particular odor, even with other odors present — and even in complex situations, such as overlapping with other scents or in different background conditions.

Replacing canines

In previous research, the opening of the locust maxillary palps to the trained odorant was used as an indicator of acquired memory. The palps were painted with non-odorous organic-chemical green paint to facilitate tracking. (credit: Debajit Saha et al./Nature Communications)

The ingenious idea in the new study by the Raman Lab is to remotely monitor neural activity from the insect brain while they are freely moving, exploring, and decoding the odorants present in their environment, which will require innovative low-power electronic components to collect, log, and transmit data.

The locusts could also collect samples using remote control. To do that, the engineers are developing a plasmonic “tattoo” made of a biocompatible silk to apply to the locusts’ wings. It will generate mild heat to help steer locusts to move toward particular locations by remote control. The tattoos, studded with plasmonic nanostructures, also can collect samples of volatile organic compounds in their proximity, which would allow the researchers to conduct secondary analysis of the chemical makeup of the compounds using more conventional methods.

“The canine olfactory system still remains the state-of-the-art sensing system for many engineering applications, including homeland security and medical diagnosis,” Raman said. “However, the difficulty and the time necessary to train and condition these animals, combined with lack of robust decoding procedures to extract the relevant chemical sending information from the biological systems, pose a significant challenge for wider application.