Scientists stitch up "lab-on-a-chip"

21 February 2010


Our more crafty listeners may be fond of whipping up a skirt or shirt with needle and thread, but now researchers in Australia have managed to use cotton thread and sewing needles to stitch together a "lab-on-a-chip" - technology that could one day be used for cheap diagnostic tests for medicine or other applications, according to research published in the journal Applied Materials and Interfaces...

Chips like this are called micro-fluidic devices - they pull tiny amounts of liquid around their surface in a tightly controlled way. And they're normally made by etching channels into silicon, glass, metal or other hard surfaces to make chips the size of a postage stamp.  But Wei Shen and his team figured that they could make a chip using cotton threads to wick liquid around surfaces instead.

The first challenge was to prepare the cotton thread. Natural cotton fibres are coated with wax, so the researchers had to use a special treatment, called plasma treatment, to remove it. Then they stitched cotton thread into paper to make little microfluidic sensors that could detect and measure different chemicals often found in the urine of patients with certain illnesses.

The team were testing for nitrite ions and uric acid, both of which can be detected by other chemicals that change colour. So, by treating the base paper with the detection chemicals before sewing them, they could make paper and thread-based detection chips.

This research is a fairly crude demonstration of the technique, but with a bit more research, it could be possible to develop cheap and effective sensors fop many different chemicals. And because the sensors are simple and cheap to make, they would be ideal for applications in the developing world, such as sensing contaminants in drinking water or soil, or for healthcare applications.


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