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A crop diagnostic lab on a microchip

New technology is bringing the science lab to the field for better, faster scouting decisions

It’s a sentence nobody likes to hear, especially in the midst of all the time pressures and the short windows of farming today. “I’m not sure about this, we’d better send a sample to the lab.”

It might be an agrologist or crop scout who says it to you, or a plant pathologist or veterinarian, but the concern is the same regardless. You’ve got a problem that needs looking into — which means it’s a problem that is costing you money — but now you have to wait for the diagnosis and the cure, and that could add up to a long chain of inconvenience and delay.

On the farm, there will be samples to collect and to prepare and send, and at the other end will be a highly trained technician, surrounded by pricey equipment and a whole lot of other samples from other sources that are just as pressing. That technician will have to perform an elaborate procedure and then report the results, and until that happens the farmer must simply wait.

Now, however, emerging microchip technology is about to change all that. The concept is known as “lab on a chip” technology, and the idea is to perform many of the basic laboratory procedures, using a specialized microchip programmed to perform on-the-spot chemical analysis.

“Folks in basic science and engineering have latched on to the idea that we can take the modern laboratory, which is housed in a large room containing many pieces of expensive equipment, and miniaturize the entire thing onto a hand-held device,” says University of Toronto chemistry professor, Aaron Wheeler. “This could allow us to take the lab out in the field and do analyses in remote locations, work with very small samples and do some types of experiments more efficiently than we can using conventional methods.”

The idea has actually been around for a while but it had to wait for the technology to catch up. The first microchips were developed in the 1950s and by the mid-’60s they were used in pressure sensor manufacturing. A decade later, a group of Stanford chemists started looking at microchips as a new way of doing lab-based chemistry, not just through computing, but developing the chips as a substitute for the laboratory itself.

As chemistry has matured so also has the laboratory. The traditional burners, beakers and flasks have been supplanted with mass spectrometers, computers and a whole array of sophisticated technology that helped speed up both experimental technique and the data crunching.

By the mid-1970s, the electronics revolution was well underway and the microchip became the foundation of computer technology. As we understood more about the physics of microchips, we found other uses for them beyond computers and they found their way into just about every common appliance.

“There’s a real Canadian success story here too,” Wheeler said. “Professor Jed Harrison at the University of Alberta was one of these folks in the early 1990s who really started looking hard at how we can miniaturize chemical instrumentation to form labs on a chip.”

Harrison took a long look at lab procedures and developed glass or silicon chips that could perform the same tasks at the micro level. Micro samples of any liquid were drawn down the tiny channels, many of them thinner than a human hair, and then the samples were run through the electrical fields generated within the chip. The chip could then collect the data and perform the analysis.

“You’re really talking about small samples, a droplet of rainwater or a small globule of oil,” Wheeler says. “You’re working in a regime that’s non-destructive where you’re using so little sample to do the analysis that your main product is unaffected.”

This is a game changer. Routine analysis can now be done on the spot with a device that a lay operator can use. Taking the lab out of the loop saves huge amounts of time by doing most of the routine procedures on the spot. Now the lab can be better used to take on more complex problems.

The medical industry was the first adopter. “I collaborate with a large multinational company called Abbot Diagnostics, and it has a subsidiary company called Abbot Point of Care, located in Ottawa,” Wheeler says. “They manufacture the I-Stat, a hand-held instrument that does many of the clinical tests that one needs to do with patients coming into a hospital emergency room. It’s another Canadian success story.”

The I-Stat has become part of the first line of emergency triage. An attending nurse puts a few drops of blood in the unit and a disposable chip cartridge runs the sample through some of the standard tests. The results are available in minutes with no trip to the lab. By developing chips for other uses, it’s possible to adapt the technology for veterinary medicine, environmental monitoring and crop scouting.

“We’re straddling the line right now,” Wheeler says. “We’re already realizing some of these benefits, but we can talk of some potential applications such as using these labs on a chip out in the field to sniff for dangerous weapons, to detect various biological events or to detect various chemical events. There’s a company in Alberta building devices to send down into oil systems to do on-site analysis of the type of oil that they’re bringing up. The range of applications is just endless.”

A cheap, simple-to-use device that identifies organic compounds would be extremely useful in both livestock and crop farming. Existing medical technology can easily be adapted for veterinary use so many of the routine diagnostics there can be programmed into an on-farm version of the I-Stat. Farmers themselves could use them to do their own diagnostics.

The same is true for crop scouting. We know that plants release identifiable chemicals into the air when they’re stressed. A chip programmed to take air samples and look for plants damaged by either insects or disease could help localize and treat minor problems quickly. Marrying this technology to a smart phone or laptop could connect the field instrument to a more elaborate wet lab if a farmer needs outside expertise. A vet or crop scientist can make a faster diagnosis if the basic lab work is already done.

We’ve seen microchips get smaller, cheaper and more powerful. We’ve also seen new manufacturing techniques that can make these things even less expensive and more flexible. Another exciting innovation is using a 3D printer to manufacture chips.

“Once you have common automatable techniques like ink jet printing, it becomes quite straightforward to set up roll-to-roll processing where you’re generating millions of devices very rapidly,” Wheeler says. “One thing my lab has kind of capitalized on is printing our devices directly on paper substrates.”

Cheap electronic devices made from paper with the circuitry printed on it could be the future of field diagnostics. The farmer of the future may have a box of these things sitting on their desk or in their workshop. These things could even be programmed for machine diagnostics. There could come a day when just about any on-farm problem can be diagnosed and solved on farm with cheap and rapid devices.

“In my sort of small corner of the world we get stuck in the area where we have these wonderful super-competent experts in our laboratories,” Wheeler says. “It’s a real challenge to kick the technology out of the nest and make it robust enough that anyone can use it.”

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