HIV diagnostics have gone mobile thanks to a new cellphone app and 3D-printed attachment that use optical sensing and micromotor motion to detect the presence of the RNA nucleic acids of HIV-1 in a single drop of blood.
Investigators from Brigham and Women’s Hospital in Boston, a teaching affiliate of Harvard Medical School, detailed this innovation in a recent paper published
in Nature Communications
The platform “integrates cellphone-based optical sensing, loop-mediated isothermal DNA amplification and micromotor motion for molecular detection of HIV-1. The presence of HIV-1 RNA in a sample results in the formation of large-sized amplicons that reduce the motion of motors. The change in the motors motion can be accurately measured using a cellphone system as the biomarker for target nucleic acid detection. The presented platform allows the qualitative detection of HIV-1 (n = 54) with 99.1% specificity and 94.6% sensitivity at a clinically relevant threshold value of 1000 virus particles/ml,” study authors wrote.
The investigators noted that the development of low-cost, accessible, and fast technologies in infectious disease diagnostics will help quell the spread of pathogens to epidemic proportions and also help to control current outbreaks in developing countries.
"Early detection of HIV is critical to prevent disease progression and transmission, and it requires long-term monitoring, which can be a burden for families that have to travel to reach a clinic or hospital," senior author Hadi Shafiee, PhD, a principal investigator in the Division of Engineering in Medicine and Renal Division of Medicine at the Brigham, said in a statement
. "This rapid and low-cost cellphone system represents a new method for detecting acute infection, which would reduce the risk of virus transmission and could also be used to detect early treatment failure."
Early detection of acute HIV infection is imperative, not only because viral replication and shedding are occurring at this stage, but also because the individual is likely not aware that they are infected, the investigators wrote. Many diagnostic tools currently in development or on the market are only measuring antibody levels.
“Most of the point-of care HIV diagnostics such as lateral flow assays, including dipsticks or enzyme immunoassays (ELISA), and OraQuick HIV test kit target the detection of antibodies against HIV and thus lack the capability to detect acute HIV infection even at high viral load of HIV,” the authors explained.
In developing countries, especially, it is sometimes difficult to efficiently test and then monitor people with HIV because of geographic constraints.
“Health workers in developing countries could easily use these devices when they travel to perform HIV testing and monitoring. Because the test is so quick, critical decisions about the next medical step could be made right there,” Dr. Shafiee said in the statement. “This would eliminate the burden of trips to the medical clinic and provide individuals with a more efficient means for managing their HIV.”
This mobile HIV diagnostic tool is just the latest in a push to make tests that are cheap, accessible, and easy-to-use for the general public. In China last year, 5 college campuses experimented with vending machine HIV test kits
, where students could purchase a kit in the vending machine, collect a urine sample in the provided container, deposit the container back in the vending machine, and view their results online within 10 to 15 days.
Similar ideas have been proposed in other cities, including in the United States. The idea is that some individuals, particularly those who may be at-risk, fear the stigma of testing in a health care setting.
“[We] have found that persons with substance abuse problems from various ethnic/racial communities in the United States and sex workers in other countries often resist HIV testing in a health care setting for fear they will test positive and will face discrimination, violence, criminal procedures, or loss of employment if their HIV status becomes known,” Celia Fisher, PhD, who directs the HIV/Drug Abuse Prevention Research Ethics Training Institute at Fordham University in New York, told Contagion®
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