22 Jun 2017

Honey, I shrunk the lab

From Our Changing World, 9:06 pm on 22 June 2017

Saving kauri trees, detecting bacteria in milk, addressing disease and infection and slowing the progress of cancer or multiple sclerosis may all be possible in the future - thanks to a new miniaturised technology.

Engineer Volker Nock, from the University of Canterbury and the MacDiarmid Institute, has developed a lab-on-a-chip that allows biologists to precisely measure the forces exerted by living organisms - on a nano scale.

Volker Nock, Ayelen Tayagui and Ashley Garrill

Volker Nock, Ayelen Tayagui and Ashley Garrill - their work on lab-on-a-chip is an engineering and biology collaboration. Photo: University of Canterbury

Lab-on-a chip as a concept has been around for many years, and the chips come in many different flavours. While they can have different functions, what they each have in common is that they are about the size of a standard microscope slide.

Nock's lab-on-a-chip contains fluid-filled channels and – most importantly – tiny flexible pillars.

Fungi expert Ashley Garrill heard about previous research measuring the forces which nematodes, or small round worms, used to bend the pillars, and he wondered if the chip could also be used with fungi.

Lab-on-a-chip sitting on a microscope

Lab-on-a-chip sitting on a microscope during an experiment. Photo: RNZ / Alison Ballance

The drilling ability of fungi

“I’ve had a long-standing interest in fungal invasive growth,” says Garrill, “in how fungi can become pathogenic and are able to grow into other organisms.”

Part of the reason that fungi are able to invade plants is that they exert enough pressure to force their way inside a plant’s cells.

Fungi are masses of thin thread-like hyphae, which together form the mycelium; the mushrooms and toadstools that we think of when it comes to fungi are just the above-ground fruiting body of a fungus.

frame grab of fungal hyphae

This video framegrab shows a fungal hyphae (visible in the enlargement as it bends to the right) after it has just knocked into and moved one of the flexible pillars (seen here as a small purple circle). Photo: University of Canterbury

Individual hyphae grow from their tips, and they are like a “pressurised drill bit” says Garrill. What interests him is being able to precisely measure this pressure, which for the size of the hyphae is very powerful.

“We’re talking micro-Newton forces, but you have to remember is that the force is applied over a very small surface area,” says Garrill.

“If you actually measure the internal turgor pressure, which is driving growth, they’ve got upwards of 10-12 atmospheres of pressure – it’s very impressive for a very small organism.”

The ever-shrinking lab-on-a-chip

Nock was happy to shrink the previous lab-on-a-chip to accommodate smaller study organisms, and PhD student Ayelen Tayagui has been tasked with learning how to grow these organisms on the chip and measure the forces they produce.

Tayagui has been working with a water-mould, related to the Phytophthora which causes kauri dieback disease. She is also trying to grow a much smaller fungus which is a type of bread mould, and to do this Nock  has had to shrink the lab-on-a-chip even further.

From about 1'30" in the video you can see a fungal hyphae bump into, and bend, one of the flexible pillars in the lab-on-a-chip.

So will this Marsden-funded research lead to a cure for kauri dieback disease? ‘That would be nice” says Garrill, although the collaborators happily admit that at the moment this is blue skies research only and won’t lead to a cure any time soon.

But Nock says this ability to measure forces could have applications for human disease.

“We are laying the ground work for future potential capability. For example, people have observed that cancer cells are very susceptible to the mechanics of the environment they grow in.

“Hypothetically if you were to expose cancer cells to mechanical forces they might revert back to something that looks like the behaviour of a normal cell.”

So watch this space – the sky may just be the limit for the ever-shrinking lab-on-a-chip.