Published online 8 December 2008 | Nature | doi:10.1038/news.2008.1286

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Blood tests using sticky tape and paper

A cheap microfluidic device could revolutionize disease diagnosis in the developing world.

Paper and tape microfluidic deviceCheaper blood tests for all, thanks to paper and sticky tape.PNAS

Chemists in the United States have made a three-cent-device to test blood or urine using only sticky tape and paper. The device does not need a pump or power source and could one day help doctors in the developing world to carry out cheap disposable tests for diseases such as HIV or malaria, its developers claim.

George Whitesides and his colleagues at Harvard University in Cambridge, Massachusetts, made the device by stacking up alternating layers of paper and double-sided sticky tape, which is impermeable to water. The sample is wicked by capillary action along tiny channels cut into the paper, and holes punched into the tape allow fluid flowing in a channel in one layer to mix with that in another.

The team has shown that the device can accommodate up to four different samples at once, and used it to test samples of synthetic urine1. The researchers were able to detect the levels of protein and glucose in each sample by spotting indicator chemicals onto the device, which changed colour in response to each substance. They then photographed the results with a camera phone and measured the colour change using computer software. Their findings are published in the Proceedings of the National Academy of Sciences.

Making a difference

The test is just the latest cheap diagnostic device to be designed by Whitesides and his colleagues. In October 2008, for instance, the researchers demonstrated that by taping plastic tubing to a $2.50 hand-held egg whisk, they could create an ad hoc centrifuge for separating out plasma from blood in a matter of minutes2.

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"It is the dream of lots of chemists to make a difference in society," says Richard Zare, a chemist at Stanford University in California. Zare says that the tool could be used in wealthy countries too to bring down the costs of health care. Patients could also use such devices to perform complex tests on their own blood or urine.

This work is "just the starting point", says Scott Phillips, a Pennsylvania State University chemist who is currently a research fellow in Whitesides's lab and one of the authors on the recent paper. The egg-whisk centrifuge and the paper-and-tape diagnostic device will need to be developed further before they're ready for the clinic, he says.

Whitesides has started a non-profit enterprise called Diagnostics for All, Phillips says, with the goal of translating these early lab prototypes into useful devices for poor countries. The team is also working on a portable protein detector that tests blood for HIV antibodies3. 

  • References

    1. Martinez, A. W., Phillips, S. T. & Whitesides, G. M. Proc. Natl Acad. Sci. 105, 19606-19611 (2008). | Article |
    2. Wong, A. P., Gupta, M., Shevkoplyas, S. S. & Whitesides, G. M. Lab Chip 8, 2032-2037 (2008). | Article | ChemPort |
    3. Sia, S. K. et al. Angew. Chem. Int. Edn 43, 498-502 (2004). | Article | ChemPort |
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