Droplets that can spot cancer and improve DNA testing: the new field of micro elastofluidics

Fluids behave differently at microscopic and nanoscopic levels. If their behaviour can be manipulated, they could be used to deliver medicines to the body, spot diseases, and grow cells that become vital medical treatments.

That’s the theory of Professor Nam-Trung Nguyen, director of the Queensland Micro and Nanotechnology Centre at Griffith University, who is in a new field called micro elastofluidics.

Nguyen gave a plenary talk at the First Australian Conference on Green and Sustainable Chemistry and Engineering, being held in Cairns this week and also just received an ARC Laureate Fellowship to make wearable devices that can connect with the body chemically.

Nguyen tells Cosmos that he first became interested in micro elastofluidics after looking at wearable medical devices, which for the moment are mostly solid.

Because liquids can be more flexible, small devices made from them could be more effective at providing medical care.

Micro elastofluidics looks at how fluids flow in solid structures, at the scale of molecules and devices.

This means drops of fluids somewhere on the scale of micrometres to nanometres (or human hairs to molecules).

It also concerns things that happen within a fraction of a fraction of a second, meaning that, even though the distances are very short, the speed is very quick.

“With high speed, and short distance, you get a lot of energy,” said Nguyen at the talk.

“This energy can help your reaction happen faster.”

What’s the catch?

“The problem is, liquid is difficult to handle at in the smaller scale,” says Nguyen.

“Liquid is formless: you cannot control it easily.”

Nguyen and colleagues have figured out some ways to manage this.

One is to coat micrometre-sized drops of liquid with a solid, such as a gel, making liquid marbles.

These tiny beads have a number of applications. One could be to fill them with medicine, for targeted drug delivery without needles.

“If I can make this type of small capsule, micrometre-sized, and use kinetic energy to ballistically pierce the skin, I can deliver the same liquid into the skin without pain,” says Nguyen.

They could also be used to grow and deliver stem cells to treat injuries, and make PCR testing – the best way to sequence DNA – more accurate, being able to show the concentration of DNA as well as its presence.

Another technique can both mix together, and separate, fluids at the microscale.

“Mixing is a problem at the microscale,” says Nguyen.

“We solve that by [adding] small, long, flexible molecules to make [fluid] elastic.”

This allows researchers to mix fluids like sweat, which can help them figure out its contents.

Nguyen and colleagues have shown that this method can be used to separate cancer cells from ordinary blood cells, potentially allowing for faster and more accurate diagnoses.

Ellen Phiddian’s airfare to Cairns was paid by the Royal Australian Chemical Institute, which is managing the First Australian Conference on Green and Sustainable Chemistry and Engineering.

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