Electronic Hedonics

Electronic noses sniff out volatile organic compounds

May 2023, phys.org

https://phys.org/news/2023-05-electronic-noses-volatile-compounds.html

Many e-noses generate different signals toward VOCs of the same concentration when the sensor is located in different parts of the "nose" chamber:

"To counteract this problem, the fluidic behavior of the gas flow needs to be well controlled," said author Weiwei Wu. "This ensures a uniform fluidic field and concentration of VOCs in the chamber and avoids generating any fake sensing characteristics."

A vertical chamber that looks much like a showerhead promotes vertical flow so gas spreads through holes at the bottom of the device and around to evenly distributed sensors.

via Interdisciplinary Research Center of Smart Sensors, School of Advanced Materials and Nanotechnology, Xidian University; Intelligent Perception Research Institute, Zhejiang Lab, Hangzhou: Controlling fluidic behavior for ultrasensitive volatile sensing, Applied Physics Reviews (2023). DOI: 10.1063/5.0141840

https://dx.doi.org/10.1063/5.0141840

Note: This problem has come up in two other papers where they talk about how the two different nostrils cancel each other out because they can't rely on evenly distributed air; it messes up the statistics, so at least with two different nostrils, you can have some error correction. See "Domestic cat nose functions as a highly efficient coiled parallel gas chromatograph", We et al. PLoS Computational Biology (2023). DOI: 10.1371/journal.pcbi.1011 https://pubmed.ncbi.nlm.nih.gov/37384594/ and "Odor representations from the two nostrils are temporally segregated in human piriform cortex", Dikeçligil et al, Current Biology (2023). DOI: 10.1016/j.cub.2023.10.021 https://dx.doi.org/10.1016/j.cub.2023.10.021

Image credit: AI Art - A Person Getting Their Head Electrocuted as Interpreted by the Internet - 2023

Perceiving the smell of lemon, geranium or eucalyptus: A study on the electrical signals behind human olfaction

Jul 2023, phys.org

https://medicalxpress.com/news/2023-07-lemon-geranium-eucalyptus-electrical-human.html

Somewhat related to electronic noses, real-live odor receptors obtained from nasal biopsies:

"Until now, nobody had measured in intact human tissue the electrical activity of cells, neurons and epithelial cells that form the olfactory epithelium of our nose in which odorant molecules are captured."

via International School of Advanced Studies, Aldo Moro University of Bari, University of Trieste, and the Otorhinolaryngology Clinic of Azienda Sanitaria Universitaria Giuliano Isontina: Andres Hernandez-Clavijo et al, Shedding light on human olfaction: electrophysiological recordings from sensory neurons in acute slices of olfactory epithelium, iScience (2023). DOI: 10.1016/j.isci.2023.107186

https://dx.doi.org/10.1016/j.isci.2023.107186

'Electronic tongue' holds promise as possible first step to artificial emotional intelligence

Oct 2023, phys.org

https://techxplore.com/news/2023-10-electronic-tongue-artificial-emotional-intelligence.html

It sounds to me a bit of a stretch right now to call this emotional intelligence; it sounds like basic chemical detection to me, but with the addition of a memristor.

The memristor is the new part, and one day we will have gustatory chips, and olfactory chips, vision chips, etc.; chips for everything; everything will have its own chip. Christmas chips and new mother chips and traffic chips for cars and ambient energy harvesting chips for sneakers and even organic chemistry chips for med students so they don't have to study. Everything will have its own chip. There won't be categories of chips, instead every single thing will have its own chip. Just not today. 

Continuing:

The artificial tastebuds comprise tiny, graphene-based electronic sensors called chemitransistors that can detect gas or chemical molecules. The other part of the circuit uses memtransistors, which is a transistor that remembers past signals, made with molybdenum disulfide. This allowed the researchers to design an "electronic gustatory cortex" that connect a physiology-drive "hunger neuron," psychology-driven "appetite neuron" and a "feeding circuit."

"When detecting salt the device senses sodium ions. This means the device can 'taste' salt."

"We are trying to make arrays of graphene devices to mimic the 10,000 or so taste receptors we have on our tongue."

via Penn State: Subir Ghosh et al, An all 2D bio-inspired gustatory circuit for mimicking physiology and psychology of feeding behavior, Nature Communications (2023). DOI: 10.1038/s41467-023-41046-7

https://dx.doi.org/10.1038/s41467-023-41046-7

E Noses Never

Read this to learn how basically e-noses are relegated to science fiction for the next 20 years at least:

How to make electronic noses smell better

Apr 2023, phys.org

https://techxplore.com/news/2023-04-electronic-noses.html

via Xi'an China Northwestern Polytechnical University: Taoping Liu et al, Review on Algorithm Design in Electronic Noses: Challenges, Status, and Trends, Intelligent Computing (2023). DOI: 10.34133/icomputing.0012

https://dx.doi.org/10.34133/icomputing.0012

'Electronic nose' built with sustainably sourced microbial nanowires could revolutionize health monitoring

Feb 2023, phys.org

https://phys.org/news/2023-02-electronic-nose-built-sustainably-sourced.html

Grown by bacteria. Great, but each nanowire needs to be programmed for each molecule, so a typical top-down approach.

via University of Massachusetts Amherst: Yassir Lekbach et al, Microbial nanowires with genetically modified peptide ligands to sustainably fabricate electronic sensing devices, Biosensors and Bioelectronics (2023). DOI: 10.1016/j.bios.2023.115147

https://dx.doi.org/10.1016/j.bios.2023.115147

A robot able to 'smell' using a biological sensor

Jan 2023, phys.org

https://techxplore.com/news/2023-01-robot-biological-sensor.html

10,000 times higher than the usual electric-based sensors, these are now biological sensors (not sure the difference). And then they program a "library of smells", so keep in mind that, like all other smell sensors out there, these don't just smell anything that happens to be in the environment -- they can only smell things that have been pre-selected and trained-on. 

via Tel Aviv University's Sagol School of Neuroscience and School of Zoology: Shvil Neta et al, The Locust antenna as an odor discriminator, Biosensors and Bioelectronics (2022). DOI: 10.1016/j.bios.2022.114919

https://dx.doi.org/10.1016/j.bios.2022.114919

New devices for conveying olfactory stimuli in virtual reality

May 2023, phys.org

https://techxplore.com/news/2023-05-devices-conveying-olfactory-stimuli-virtual.html

Aerosols and atomizers add bulk to VR gear and entail bottle filling and cleaning. This new approach uses paraffin imbued with scents, released by a temperature-sensing resistor that controls a heating element - the more heat the more scent. But wait -- magnetic induction coils pull heat away from the face to cool the wax quickly when the scent is no longer needed. 

The removal of scent is actually the harder problem to solve than the introduction of scent in these kinds of systems.

via City University of Hong Kong, Beihang University and Shandong University: Yuhang Li, Soft, miniaturized, wireless olfactory interface for virtual reality, Nature Communications (2023). DOI: 10.1038/s41467-023-37678-4

https://dx.doi.org/10.1038/s41467-023-37678-4

Promiscuous Pattern Recognition

Study reveals how smell receptors work

Aug 2021, phys.org

https://phys.org/news/2021-08-reveals-receptors.html

Big smell news - for the first time ever, using cryo-electron microscopy, we can see an olfactory receptor in action. And as expected, it doesn't work like any other receptor.

Odorant receptors are known for their 'promiscuous chemical sensitivity;' that's a scientific term, by the way. It means that any one receptor might be sensitive to hundreds of molecules, so it's been really hard  to figure out what makes any particular molecule match with a receptor.

They looked at the jumping bristletail (surprise - not the fruit fly) because it has only five types of receptors, and because one of those receptors (OR5) is really broad, responding to 60% of the smell molecules they presented to it (promiscuous).

So they look at this receptor in its default state, and then again as they expose it to smell molecules (either eugenol or DEET).

And? Its ion channel pore dilates. That's it. Both of the competing theories about how smells work were wrong. It turns out they work via nonspecific chemical interactions -- they are not recognizing a specific chemical characteristic, but something more general about the molecule itself.

And there you have it! Olfaction is still one of the strangest senses we have.

Don't forget to thank cryo-electron microscopy, and the hundreds of scientists who have been trying to figure this out over the past hundred years.

via Rockefeller University: del Mármol, J., Yedlin, M.A. & Ruta, V. The structural basis of odorant recognition in insect olfactory receptors. Nature (2021). https://doi.org/10.1038/s41586-021-03794-8

Behold the Odor Coder

AKA The Nose Decoder

It will be a very long time before a robot can smell, but it seems we are now a giant leap closer.

Researchers at New York University's Langone Health Center have simulated olfactory perception with a synthetic electronic odor signal. In laymen's terms, mouse noses were tricked into thinking they smelled something when it was actually just an electrical signal. This is kind of like the way you can open someone's skull and zap certain parts of their brain, and they will feel tingles in corresponding parts of their body, even though you're not touching those parts of their body (don't try this at home though).

In this case, the brain-zapping was accomplished by way of optogenetics, a field that if you don't know, you better, because it's taking over neuroscience.

Optogenetics is where you genetically modify neurons to be sensitive to light in the same way they are normally sensitive to electrical impulses. This creates neurons that can be activated with light instead of electricity. Fiber optic cables are then threaded to these light-sensitive neurons, giving us control at the individual neuron level, and in the case of this study, it gave the researchers control of a bunch of olfactory neurons all at once (although in the paper you may see them refer to these as "glomeruli," which are like bundles of neurons that share similar coding patterns). And for reference, the only way an olfactory receptor, or glomeruli, in your nose has ever been stimulated has been with an odorous molecule, and never with an electrical signal. (Someone feel free to correct me on this.)

But who cares?

Scientists who study these kinds of things; they care. If you can make a mouse think it's smelling something that you created from scratch (i.e., an electrical odor representation), then you can modulate that signal however you want, and test the effect on the other end. With actual odor molecules, which are the usual way to stimulate olfactory neurons, this is too difficult.

I can try to explain the importance of this in one other way -- Let's say you get your whole nose-brain hooked up to these fiber optic light tubes. (You would first need to re-code all those genes to be light-sensitive, of course, so I hope you have a good insurance plan). Now every single neuron that lets you smell can be both activated and monitored by pulses of light.

Then we have you smell a whole batch of real, molecular odorants*, and we watch the electric signals that naturally fire in your nose-brain as a response to those signals. We record those signals, and then recreate them with electrical impulses (or light pulses), and all of the sudden, you can smell the same odors, but without the odorants.

We would then have reverse engineered the signal on the receiving end of the olfactory system. This is ultimately how the artificial cochlea was created, and the artificial retina. And now you can go ahead and ask the owner of Neuralink how far away they are from threading these cables into our olfactory epithelium, and also whether your insurance covers optogenetically-enhanced genes, and you will be one step closer to the future of olfaction. And the next time we go into global lockdown (100 years from now?), we will not suffer for lack of olfactory stimulation.

*The term "molecular odorants" has not had to exist until now, kind of like an "acoustic guitar" did not exist until the advent of the electric guitar.

Notes:
Manipulating synthetic optogenetic odors reveals the coding logic of olfactory perception. Edmund Chong, Christopher Wilson, Shy Shoham, Stefano Panzeri, Dmitry Rinberg. Science 19, Jun 2020, Vol. 368, Issue 6497, eaba2357. DOI: 10.1126/science.aba2357

News Release:
Scientists decode how the brain senses smell, NYU Langone Health, June 2020.

Post Script:
There are also some interesting results from this study that support the mostly-uncontroversial yet definitely misunderstood theory of information processing in the olfactory bulb, which is that the detection of odor-representations is more of a combinatorial process, and less of a one-to-one system of odor molecules and neuron receptors. And, this combinatorial perception theory is a primary reason as to why we cannot comprehensively organize olfactory experience into subsets or primary odors. (And the reason for writing a book about the language of smell.)

Olfaction Meets AI

Headline reads like this:

TEDGlobal: The computer that can smell explosives

Aug 2017, BBC

And inside:

Nigerian Oshi Agabi’s modem-sized device - dubbed Koniku Kore - could provide the brain for future robots. It is an amalgam of living neurons and silicon, with olfactory capabilities — basically sensors that can detect and recognise smells.

And an explanation:

While computers are better than humans at complex mathematical equations, there are many cognitive functions where the brain is much better: training a computer to recognise smells would require colossal amounts of computational power and energy, for example.

The prototype device shown off at TED - the pictures of which cannot yet be publicly revealed - has partially solved one of the biggest challenges of harnessing biological systems - keeping the neurons alive. "This device can live on a desk and we can keep them alive for a couple of months," Agabi told the BBC.

And what do we think about this?

As much as this story is pretty nuts (if the sentence “They can live on a desk” doesn’t make your head spin…), it’s all too common a story in the tech world. Not that it’s fake news or anything, but let’s just say it is misleading to talk about “smelling robots” in this way.

The less interesting truth is that they can only be trained to smell specific molecules, not even signatures, or combinations, of molecules. A system able to smell “anything that might come up,” and able to use that information for something important, such a system could not be trained. Well, hmmm,  we get trained to do this from birth, in fact we are already learning about our olfactory environment in utero.

So if we want AI to meet olfaction, what we need to do is keep them alive for a lifetime, and give them a body, and friends and a job. You know, just like a real person. They would need to learn from the ground up, just like a real person.

However ---

There is a point being made here by Mr. Agabi that is totally in-line with the thesis of Hidden Scents. The way we use computers today will eventually be supplanted by something else. Traditional computation will still be useful, but something else will take us beyond the capacities of today’s technology (whole lotta talk in the sci-fi sphere of quantum computing, for example).

As of now, neural networks are taking us in a new direction. Granted they were used back in the 80’s, but only recently have they become a marked change in computing technique. (I like to note here the contemporaneous link between the architecture of neural networks and how it is the same thing used to mine bitcoins – the processor is no longer the key component, it’s how many graphics cards you have all wired together.)

The olfactory bulb, the crux of the olfactory system, from an information processing point of view, is a model neural network. And the fact that it’s already connected to the limbic system – the thing that makes us move, the thing that makes our bodies work, and even our emotions – this makes it a model system for so much more.

*Anyone with more comp sci knowledge than me please feel free to correct as I am no expert and speaking in pretty broad, possibly misunderstood, terms.  

Synthetic Tongue

Snakes, and many reptiles, have a split tongue because they smell with their tongue, and the two-tongues let them know which direction the smell is coming from. Humans, however, have split tongues because they want to. Tongue-splitting is a form of body modification.

In other news:

Researchers use a synthetic 'tongue' to sort out whiskies

Jun 2017, phys.org

“These synthetic "tongues" can highlight similarities between whiskies, but they can't identify an unknown whisky from scratch, he says, "You start with a sample that you know is the real McCoy. Then you look at another sample, and you can say whether it's the same sample or it's not." In other words, these tongues would be great for spotting counterfeits of expensive luxury whiskies.”

Note that this synthetic tongue cannot taste like we do. Well, first of all, note that taste and smell are very similar; Humans don’t smell with our tongues like snakes do, but most of what we “taste” is actually perceived by our nose. Nonetheless, this synthetic whisky tongue still does not work the same way as our perceptive apparatus. This tongue can only identify pre-determined patterns. You give it one flavor profile to ‘sense,’ and ask whether a new sample matches that or not. You can’t give it any old thing and ask “what is this?”

Perhaps the most amazing thing about our olfactory sensory apparatus is that it begins as a blank slate, with no hardwiring for any smells whatsoever. Everything we smell, and everything we can identify, we learn. If we want this synthetic whisky tongue to be able to identify a whisky from scratch, we need it to grow up like a little human, learning every single smell from scratch, just like us.

This is the same old story with all of these reverse-engineered smell-and-taste organs. They cannot be used to sense the way we do, where they are able to identify any combination of hundreds of thousands chemicals. Instead, they are given one job, to smell one thing, and they either smell it or they don’t. It’s like making an eye that is only for seeing the color red. Red or no red. It doesn’t know the Pantone catalog, only that one red.  Instead of choosing from the infinite answers to the question “what do you smell,” these prostheses can only choose from two possible answers, yes and no.

To program a truly synthetic tongue, or better, a synthetic nose, is still very, very far beyond our capacity. In the meantime, things will progress as they do; one piece at a time, dividing the human capacity for information-gathering into myriad discrete operations, and recreating ourselves through the fractured image of technology.

Image source: link

At the Cutting Edge of Olfaction

This is a really cool book on the state of the art as well as the future of artificial olfaction.

Human Olfactory Displays and Interfaces: Odor Sensing and Presentation

Takamichi Nakamoto (Tokyo Institute of Technology, Japan). 2013. 555 pages. direct link

[Description]

Although good devices exist for presenting visual and auditory sensations, there has yet to be a device for presenting olfactory stimulus. Nevertheless, the area for smell presentation continues to evolve and smell presentation in multimedia is not unlikely in the future.

Human Olfactory Displays and Interfaces: Odor Sensing and Presentation provides the opportunity to learn about olfactory displays and its odor reproduction. Covering the fundamental and latest research of sensors and sensing systems as well as presentation technique, this book is vital for researchers, students, and practitioners gaining knowledge in the fields of consumer electronics, communications, virtual realities, electronic instruments, and more.

[From the Foreword, by Jiri Janata]

Olfaction and taste are two truly chemical senses in which the interaction of the molecule and/or group of molecules with olfactory receptors triggers a chain of complex physiological events, which end in a cognitively interpreted “sensation.” In humans, such sensation can be articulated and can lead to various descriptions that can be anything from general, e.g. “pleasant/unpleasant,” to highly specific, such as chlorine, ammonia, or cinnamon. For most vertebrates, smell is existentially important because it predefines actions as diverse as “to run” or “to mate.” It could be argued that some animals are biological machines whose sole purpose in life is to reproduce and olfaction is one of the key enabling functions.

For many years, engineers and scientists have been fascinated with the idea of explaining olfaction and constructing artificial olfactory machines that do just that. Thus, biology has once more inspired creative activity that has resulted in hundreds of worthwhile and also some questionable publications. It has even received recognition at the Nobel Prize level. The present book belongs to this enormously fertile, but complex area of scientific endeavor.

[From the Preface, by Takamichi Nakamoto]

Although a human interface for vision and audio has been already been developed, an olfactory interface has not. However, people are becoming interested in olfaction as the next-generation human interface. A human interface for olfaction is composed of an olfactory display and an odor sensing system called an electronic nose. An olfactory display is an output of a machine, whereas the odor sensing system is its input. These are important to realize a human olfactory interface. Since an odor sensing system has been studied for last two decades, the researcher population is relatively large. An international conference of machine olfaction is held every two years. However, there are not many olfactory-display researchers, since the olfactory display only recently evolved in virtual reality. Although both fields have been studied separately, it is indispensable to see and understand both the olfactory display and the odor sensing system for developing human olfactory interfaces and their applications.

The Ever Impending Electronic Nose

CMOS Sensor, image source

The electronic nose has been coming forever. We already have artificial noses in the form of mass spectrometers. The new kind use integrated circuits, the same CMOS chips that are in cellphones. They aren’t tied to a thinking, feeling human, but at least the initial step of identification is happening.

This article in particular is touting the use of an artificial nose to analyze breath samples, citing that “breaths contain gases from the stomach and that come out of blood when it comes into contact with air in the lungs. The breath test is a blood test without taking blood samples. Breath contains information about practically every part of a human body.”

This is good stuff, and explains why your breath starts to smell funny when you’re hungry, or why diabetic-breath smells like acetone, but I must keep going and repeat the sales pitch of this scientist:

"If you think about the industry around sensors that emulate our senses, it's huge," said Dr. O, also a professor in the Erik Jonsson School of Engineering and Computer Science and holder of the Texas Instruments Distinguished University Chair. "Imaging applications, hearing devices, touch sensors—what we are talking about here is developing a device that imitates another one of our sensing modalities and making it affordable and widely available. The possible use of the electronic nose is almost limitless. Think about how we use smell in our daily lives."

But yes, let’s think for a minute about how we use smell in our daily lives. Smell is so below the radar that we don’t consciously register most of its ongoings. So when we take this CMOS sensor to a brain, what exactly would we like it to do? Of course we can’t engineer the olfactory bulb itself, or the subsequent limbic system (in concert with our memory) that ultimately creates our experience of smell. But if we were to isolate it, and use it for specific things, like breath analysis, then what else would it do?

Gas leaks, obviously. Maybe it could alert my roommate to change the litter box? Or tell a parent that their teenager was drinking last night (that’s a simple breathalyzer built into the air system of the house; watch out kids). You would think we’d already have one to smell the maple syrup smell coming from the burning transmission fluid in your engine. And what else? Can I smell the presidential candidates with my CMOS supernose? Who knows. Smell a house on Zillow? Let’s bring it to Japan and see what they do with it.

Post Script:

On thinking about this further, I must stress the difference between what I’ll call active smelling and passive smelling. What we do as humans is passive smelling. For the most part, we are not actively looking for a particular smell. (And, in fact, this is no way to smell, unless you’re a fragrance artist.) It’s more like the Tao of Perception – you must have a “soft awareness” where you are ready for any smell, but you’re not actively smelling for anything in particular. That’s just the way smell works. So this is passive smelling.

Active smelling would be a sensor fitted for one particular odor compound. Acetone, for diabetic-breath, for example. Or it may be fit for a bunch of things on top of that. But you could never fit the sensor for all potential smells. That’s not how the human epithelium works. We would need an artificial olfactory bulb for that, because the bulb turns our 450 receptors into the trillion potential smells available. And further, to attach that to meaning, we would need, again as mentioned above, an entire body, and more than that, a body that has lived from birth. A Frankenstein created at 20 years old would not be able to smell. This must be a baby Frankenstein we’re talking about here, zygote even.

In closing, we can’t have an electronic nose that is “open ended.” It can look for particular things on Zillow – mold? Wet paint? (who cares) Frito Feet? (that’s the smell of dog feet, which could indicate a pet lived in the house?). Thanks for listening.

Notes:

Electronic nose using CMOS integrated circuits analyzes breath

phys.org, June 2016

Everybody Wants Explosive Sniffing Robots

image source

Mutant mice become 'super sniffers'

BBC News, July 2016

On the heels of another mention in the news of remote control insectobots, we see a trend in artificial olfaction: explosives sniffing robots. If there's one thing a robo-nose is good for, it's detecting dangerous things in our environment. After all, this is a major purpose of olfaction. Actually, this time they aren’t robot noses, they’re regular animals, but they’ve been genetically engineered to have special olfactory appendages, or to be more specific, they’ve been engineered to smell one thing really well.

Furthermore, and a point made in the article, humans can become super sniffers for any smell as long as we’re trained to do it. I inadvertently made myself super sensitive to mold after living in a basement apartment for seven years, after said apartment was completely covered waist high in dripping penicillium colonies, and I can now smell it in amounts way below what normal people require.

*In fact, I’ll say this here – mold is everywhere and I know because I smell it everywhere. Not the killer kind, just the regular everyday mold-on-your bread kind. We already know it’s everywhere, just like yeast is floating around us right now, no matter where we are. But it comes in all different kinds, old mold, new mold, wet mold, dry mold. Every building I go into I smell it somewhere, on certain days it’s growing on trees and floating past your face, on certain people it’s pumping out of the holes in their clothes, coming off of their hair or the dark parts of their bodies, or the crevices of their cottonsuits; it’s everywhere. In fact, last night I went to an outdoor bar/patio for drink;, it’s been raining on and off for the past few days, and I could not get away from it – the smell of mold, that is – I suspect it was coming from underneath the outdoor patio, which has a tendency to be wet and dark, but later that night after I got home I was bothered by a mold I don’t get every day – metal mold – not sure what this is but I know what it smells like; I must have had my hand resting on their (moldy metal) patio furniture all night I had to wash my hands a few times before going to sleep. Anyway, I'm for hire. Although, it seems like my job is being taken over by robots and genetically engineered animals

Insectobots

Where taxidermy meets cybernetics meets aeronautics meets morality: The Copter Cat

Locusts are now being put to use as remote control bomb sniffers. First though, let us not forget that it was only a year ago that the commercial market saw its first real moral problem with the intersection between living creatures and automation: cockroaches were sold with little backpacks that were meant to be wired directly into their motor cortex and steered around by little biohacking boys and girls. And don’t forget this guy who turned his dead cat into a remote control helicopter.

Back to the locusts. I don’t know about you, but I thought locusts looked like grasshoppers, and at about the same size. But in the picture used for the leading article here at the BBC, this thing is as big as my forearm. So maybe these are giant locusts. (The name locust is derived from the word for lobster.)

Their wings will have a biocompatible plasmonic tattoo imprinted on them which will heat up by remote control to manipulate the locust’s wings to fly one way or another in order for them to be guided into dangerous or remote areas. A tiny chip interfacing with the locust-olfactory-brain will then detect explosives chemicals. A single sensor can only detect a single chemical, but a locust’s nose-brain is so much more effective than any computer we know. Not only does it have more sensors, but they combine together to be able to recognize thousands of chemicals in their environment, and they can do this despite there being so many chemicals around us in the first place. The locust is much more accurate than anything we can make.

Baranidharan Raman, associate professor of biomedical engineering in the School of Engineering and Applied Science Washington University and (locust olfaction expert) explains in the BBC article: "Even the state-of-the-art miniaturised chemical-sensing devices have a handful of sensors. On the other hand, if you look at the insect antennae, where their chemical sensors are located, there are several hundreds of thousands of sensors and of a variety of types." The robo-locosts – both the insect and their fitted chip – will be trained to sniff out specific smells – not specific molecules, mind you, but “smells,” as in the holistic olfactory identity of a thing, which is more complex than a single molecule.

Instead of making a fully artificial drone-nose, it makes more sense to mix a bit of both. We know how to make things fly like an insect already so that isn’t the bonus; but the nose, or the insect olfactory system to be specific (they don’t have nostrils but antennae) cannot yet be replicated. In fact, we’re nowhere near it. As the venture to create the first high fidelity electronic nose ramps up and up, it looks like we might have to change course a bit and take a page out of Mary Shelley’s book. Frankensteins for life. 

Notes:

Locusts to 'sniff out explosives'

BBC News, July 2016