Harvard scientist fashions cheap, easy-to-use diagnostic test

February 21st, 2009 - 6:35 pm ICT by IANS  

Washington, Feb 21 (IANS) A Harvard scientist has developed a versatile and low cost test that can detect infectious or chronic diseases with only a tiny sample of urine or blood.
George Whitesides, a Harvard University professor, is coupling advanced microfluidics with one of humankind’s oldest technologies - paper. The finished devices are paper squares roughly the size of postage stamps.

The edge of a square is dipped into a urine sample or pressed against a drop of blood, and the liquid moves through channels into testing wells. Depending on the chemicals present, different reactions occur in the wells, turning the paper blue, red, yellow, or green.

A reference key is used to interpret the results, elaborates the study from Technology Review, to be launched by noted policy maker M.G.K. Menon at MIT’s Emerging Technologies upcoming conclave in New Delhi.

The squares take advantage of paper’s natural ability to rapidly soak up liquids, thus circumventing the need for pumps and other mechanical components common in microfluidic devices.

Harvard researchers have made the paper chips into a three-dimensional diagnostic device by layering them with punctured pieces of waterproof tape. A drop of liquid can move across channels and into wells on the first sheet, diffuse down through the holes in the tape, and react in test wells on the second paper layer, said a Harvard release.

The ability to perform many more tests and even carry out two-step reactions with a single sample will enable the device to detect diseases (like malaria or HIV) that require more complicated assays, such as those that use antibodies. Results appear after five minutes to half an hour, depending on the test.

These findings were published in the inaugural issue of the Indian edition of Technology Review, a 109-year magazine from Massachusetts Institute of Technology (MIT).

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