A pocket-sized $10 device that can “amplify” DNA is promising a cheap, portable method for diagnosing HIV and TB. Like existing lab equipment, the device uses the polymerase chain reaction (PCR) to amplify a sample, but is does this in as little as 20 minutes, rather than the hour or two usually needed. “I hope this will make PCR more available,” says Victor Ugaz of Texas A&M University in College Station, whose group developed the device.
To amplify a small sample of DNA it is first heated to a series of different temperatures to make its double strands uncoil and…
