Health and Medicine

Cheap Smartphone Dongle Diagnoses HIV And Syphilis In 15 Minutes

February 5, 2015 | by Justine Alford

Photo credit: Samiksha Nayak for Columbia Engineering.

The list of things that our smartphones can do these days is virtually endless. They can help you learn a new language, brew you a coffee from bed, track your fitness, plan your night out and keep you entertained for hours on end, to name just a few. Now, adding to the ever-growing number of things they can do, scientists have developed a cheap accessory that turns a smartphone into a mobile diagnostics lab.

Developed by researchers at Columbia Engineering, the low-cost dongle can simultaneously detect two markers from syphilis, and one from HIV, in just 15 minutes. What’s more, it only requires a finger prick of blood, and runs on power drawn from the smartphone, eliminating the need for extra batteries.

The small, lightweight device contains a lab on a chip consisting of a disposable plastic cassette containing the necessary reagents for the tests. Blood from a patient is drawn through microscopic channels where it then meets chemicals that react with HIV and syphilis antibodies to produce a color change. This can then be picked up by a set of photocells in the dongle, and the results are then sent to an app on the attached smartphone or computer.

Because this device would be particularly useful in remote areas that do not always have electricity, the engineers designed it in such a way that it requires very little power. Rather than sucking up the blood with an electrical pump, the researchers installed a large button that creates a vacuum when pressed down which draws the sample through the hair-sized channels. It also uses an audio jack for power and data transmission, meaning it doesn’t need a battery and can be hooked up to any compatible smart device. According to the researchers, a fourth-generation iPod Touch could conduct 41 tests on a single charge.

The team conducted a small field study to test out the device in Rwanda, which yielded encouraging results. As described in Science Translational Medicine, health care workers were given just 30 minutes of training before 96 patients were tested using finger prick samples. They found that the test rivaled gold standard lab tests and was able to correctly detect infections 92 to 100% of the time. Although it missed one case of syphilis and falsely diagnosed syphilis infections 14% of the time, the device is still extremely useful because false positives would be picked up later on after the patient is sent for further tests and treatment.

Amazingly, the dongle only costs around $34 to produce, which is significantly cheaper than traditional laboratory equipment which can cost close to $20,000. Furthermore, the disposable cassettes are predicted to only cost a few dollars. And because samples don’t need to be shipped to labs for analysis, results can be discussed with the patient straight away, reducing the time between diagnosis and treatment.

The team behind the device is now planning a larger trial, and if the results are positive, hopefully they can soon start putting it to use in areas in need of better disease screening.

[Via STM, Science, Columbia University and Live Science]

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