We noticed you're browsing in private or incognito mode.

To continue reading this article, please exit incognito mode or log in.

Not an Insider? Subscribe now for unlimited access to online articles.

Rewriting Life

Smartphone Test for HIV and Syphilis Costs Pennies

A phone attachment using cheap disposable cartridges rapidly tests for HIV and syphilis in a Rwandan trial.

HIV and syphilis can kill or cause lifelong infirmity, and existing lab-based tests are expensive.

In a small trial in Rwanda, a $34 smartphone attachment rapidly and accurately detected the presence of HIV and syphilis antibodies in drops of blood taken from pregnant women. The work, described in a paper published today in the journal Science Translational Medicine, demonstrates that laboratory-quality diagnostics can be run on a pocket-sized device that works well in field conditions.

A smartphone attachment with a microfluidic mixing chamber connects to a smartphone’s audio jack for power.

The plastic attachment, about the size of the phone itself, uses disposable cartridges costing just pennies. A health-care worker loads a blood sample, which mixes with chemicals called reagents in microscale channels within the cartridge.

Gold nanoparticles bind to antibodies, and silver nanoparticles form a film around the gold particles. This silver film blocks light shined through the finished sample, indicating the test result within 15 minutes. The result is automatically loaded into the phone’s storage.

The test replicates antibody-based tests known as ELISA but does not require expensive lab equipment. In the study, which involved 96 people, the accuracy was almost as good as it is with ELISA, says Samuel Sia, an assistant professor of biomedical engineering at Columbia, who led the work.

Several groups are working on similar microfluidic-chip technologies. A decade ago, Sia founded a startup, Claros Diagnostics—later sold to OPKO Health of Miami—to market a version of his system for prostate ­cancer tests (see “Prostate Cancer Results While You Wait”  and “Innovators Under 35: Samuel Sia”).

In the past few years, members of Sia’s research group have miniaturized the technology, reduced its power requirements, and integrated it with everyday mobile devices. The tiny amount of current available in a smartphone audio jack is all that’s needed to power the sensing and data management. (One charge of an iPod Touch can power 41 tests.) “We sort of smartphoned it, in a way,” Sia says. “We’ve greatly reduced the size, cost, and power requirements.”

Sia’s group also created software that records the results of tests and upload those results to a server—a crucial function for data collection and retention. The group worked on HIV and syphilis markers as part of a USAID program on maternal health.

“This work is a proof of how technology can improve diagnosis and care, making it faster and simpler and cheaper without compromising the existing quality,” says Sabin Nsanzimana, the manager of the sexually transmitted disease division at Rwanda’s Ministry of Health. However, “it may take time, or bigger studies,” to see wider adoption, Nsanzimana says.

Sia says he is now planning a larger-scale field trial and sees far broader implications for smartphone-based diagnostics. “While we’ve been working on HIV and syphilis, this technology can be used for a variety of different applications, obviously,” he says. “You could see health-care systems transformed in a very fundamental way if consumers can get precise measurements in a decentralized manner.”

Become an MIT Technology Review Insider for in-depth analysis and unparalleled perspective.

Subscribe today
More from Rewriting Life

Reprogramming our bodies to make us healthier.

Want more award-winning journalism? Subscribe to Insider Plus.
  • Insider Plus {! insider.prices.plus !}*

    {! insider.display.menuOptionsLabel !}

    Everything included in Insider Basic, plus the digital magazine, extensive archive, ad-free web experience, and discounts to partner offerings and MIT Technology Review events.

    See details+

    Print + Digital Magazine (6 bi-monthly issues)

    Unlimited online access including all articles, multimedia, and more

    The Download newsletter with top tech stories delivered daily to your inbox

    Technology Review PDF magazine archive, including articles, images, and covers dating back to 1899

    10% Discount to MIT Technology Review events and MIT Press

    Ad-free website experience

You've read of three free articles this month. for unlimited online access. You've read of three free articles this month. for unlimited online access. This is your last free article this month. for unlimited online access. You've read all your free articles this month. for unlimited online access. You've read of three free articles this month. for more, or for unlimited online access. for two more free articles, or for unlimited online access.