In all cases, animals are thought to detect chemicals that people emit through body odor or respiration. The mixture of chemicals can vary depending on a person’s metabolism, which is thought to change when we get sick. But dogs are expensive to train and care for. And making a device that mimics a dog’s nose has been extremely difficult to do, says Debajit Saha, one of the scientists behind the latest work, which has not yet been peer-reviewed.
“These changes are almost in parts per trillion,” says Saha, a neuronal engineer at Michigan State University. This makes them difficult to pick up even with state-of-the-art technologies, he adds. But animals have evolved to interpret such subtle changes in odors. So he and his colleagues decided to “kidnap” an animal’s brain.
COURTESY OF RESEARCHERS
Researchers chose to work with locusts because these insects have been well studied in recent years. In a preliminary setup, they surgically exposed the brain of a live lobster. Saha and his colleagues inserted electrodes into the lobes of the brain that receive signals from the antennae of insects, which they use to detect odors.
The team also grew three different types of human oral cancer cells, as well as cancer-free human oral cells. They used a device to capture the gas emitted by each of the cell types and delivered each of them to the antennae of the locusts.
The lobster brain responded to each of the cell types differently. The recorded electrical activity patterns were so different that when the computer inflated the gas of a cell type into the antennas, they were able to correctly identify whether the cells were cancerous only from the recording.
This is the first time a live insect brain has been tested as a tool to detect cancer, says Saha.
Natalie Plank, who is developing nanomaterial-based health sensors at Victoria University of Wellington in New Zealand, believes the work is “very cool”. “The potential of just being able to breathe with something and then know if you’re at risk for cancer … is really powerful,” he says.
In the experiment, the team took multi-lobster brain recordings and combined their responses. Recordings of 40 neurons are currently needed to get a clear signal, meaning the system requires between six and 10 lobster brains. But Saha hopes to use electrodes that can record more neurons, which would allow him to obtain recordings from the brain of a single locust. He also hopes to be able to use his brain and antennae on a portable device, which could then be tested on real people.
