How does the nose know what it knows?

Many people would describe themselves as sensitive to smells—an open bin makes them retch, perfume makes them sneeze, and they can smell spoiled milk from a mile away. But even the most sensitive human nose has nothing on the odorant receptors of an insect, which are so sensitive they can smell a single molecule, as well as easily detect a wide range of chemicals.

Dr Natalie Plank in the lab

These factors mean insect odorant receptors have significant potential in artificial nose technologies. However, to make them useful to science, we need to know more about their structure and function.

Dr Natalie Plank from Te Herenga Waka—Victoria University of Wellington’s School of Chemical and Physical Sciences and the MacDiarmid Institute, is leading a team using nanoelectric devices to investigate how olfactory receptors transmit signals to insects about their surroundings. She’s working alongside Dr Colm Carraher from Plant & Food Research and Dr Adam Micolich from the University of New South Wales.

“Working with odorant receptors is very exciting. You can start to imagine lots of real-world applications, which I find very motivating,” Dr Plank says.

Potential applications include detecting diseases by smell, sniffing out invasive species before they enter the country and compromise ecosystems, and telling us if food is still safe to eat so it doesn’t get wasted.

The nanoelectric devices used in this research are the culmination of many years work for Dr Plank, who has been researching the devices for most of her career.

“I find the idea of tiny wires doing strange things very interesting,” she says. “It’s really fun, although it’s definitely challenging as well.”

In this project, the tiny wires are “seeing” what the proteins in the insect olfactory receptors are doing. When the electric charges from the wires interact with the receptors, Dr Plank and her team use this interaction to learn more about how the receptors work.

The research is still in the early stages, but so far the team has seen some promising results.

“By using the nanoelectric devices, we have established that we can measure the receptors detecting different target scents,” Dr Plank says. “This is very much initial research, but it has presented us with many more questions about this topic, which is always exciting as a scientist.”

Dr Plank and her colleagues will continue investigating the receptors and hope to pave the way for real-world applications.

Dr Carraher will be making changes to the receptors that will give the team new ways to examine their behaviour. Dr Micolich will be developing new nanoelectric devices that can be used to further investigate how the receptors work.

“It’s been really good to work with a team of molecular biologists and be exposed to different skill sets and areas of expertise,” Dr Plank says. “By working together, we have been able to tackle some interesting topics that I wouldn’t have been able to tackle otherwise.

“Having a broader team like this and working together really is the key to success.”

This year, the research project received nearly $1 million from Te Pūtea Rangahau a Marsden—the Marsden Fund. The grant provides research funding for three years.