Glasgow: Microtubes for use in microfluidics

Research lead

Scientists at Glasgow University have grown microtubes from crystals of inorganic compounds, an advance that has major implications for the microfluidics industry, with applications in medical sensing being one of the major prospects.

The tubes are grown from crystals of Keggin-net, a type of polyoxometalate, which comprises large clusters of metal and oxygen atoms. The scientists are able to control the rate of tube growth by varying the concentration of cations in the solution, and the direction of growth by altering the polarity of electrodes placed around the crystals. They have demonstrated the tubes are watertight.

Leroy Cronin, who leads the group in the Department of Chemistry, said this discovery, “Presents the possibility of growing microfluidic channels in any pattern you want, controlling the rate of growth and direction like an Etch-a-Sketch, and then flowing liquids through the tubes.”

When severed, the tubes, which can grow at rates of between one micron to more than 100 microns per second, continued to grow from the point where they were cut. They can also negotiate obstacles and merge with each other. Tube diameters were as small as 20 microns. Tubes many millimetres long were observed before growth ceased.

The research team plans to publish their recipe for growing the microtubes so that others can experiment with different materials. Different polyoxometalates will vary the chemical properties of the tubes, enabling them to react with different cation solutions presenting various possibilities for applications in medical sensing, for example.

“It’s an intriguing process and one which might have many exciting applications in making micro-fluidic devices,” said Cronin. Because it appears that many types of polyoxometalates can be used to grow tubes, they could be designed to have a variety of functions and applications.”

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