The accessory, called the immunoassay tester, isn’t found in any Apple Store of course, but it has already been used on about 100 patients in Rawanda by healthcare workers on the field. The technology comes packaged in a small dongle that draws power from the smartphone via the headphone jack. Data is pushed to the phone through the same connection, and an app developed for diagnosis does its job with this data. The test results are displayed on screen. One charge of an iPod Touch can power 41 tests. “We sort of smartphoned it, in a way,” said Samuel Sia, assistant professor of biomedical engineering at Columbia, who led the work. “We’ve greatly reduced the size, cost, and power requirements.”
The dongle is currently being tested as part of a program to reduce mother-to-child transmission of these diseases. Using this new technology is quite easy too. Workers only needed about 30 minutes of hands-on training to get familiar with the set up.
The tester is much smaller, cheaper and more convenient than traditional lab equipment used for such diagnosis. These setups are called ELISA set-ups, and require a few feet of bench space, and manufacturing costs can reach $20,000. Colombia’s tester on the other hand costs a minuscule $34 to manufacture.
The plastic dongle is about the size of a phone and uses disposable cartridges that cost a fraction of a dollar. The blood sample is mixed with chemicals called reagents in microscale channels within the cartridge. Gold nanoparticles bind to antibodies, which are then covered by a film of silver nanoparticles. This film blocks light shined through the finished sample, indicating the test result.
The tester is described in a paper published in the journal Science Translational Medicine[].
