Microfluidic Rapid and Autonomous Analytical Device (microRAAD) to Detect HIV from Whole Blood Samples
Early Human Immunodeficiency Virus (HIV) testing is critical to preventing transmission and providing treatment to HIV-positive individuals, yet an estimated 30% of HIV-positive individuals do not know their status because of barriers to early diagnosis. Readily accessible, highly sensitive, and rapid diagnostic tests would enable patients prompt treatment with anti-retroviral therapies and reduce transmission. However, existing HIV diagnostic technologies either do not detect early stages of infection or require multiple days of laboratory processing, delaying notification of patients status.\n\nMolecular techniques that amplify HIV RNA can detect the earliest stages of infection, within 8-10 days after transmission. However, most of these molecular assays require cold-chain storage of reagents, significant sample preparation, and extensive laboratory infrastructure. To achieve early detection, we developed a reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay with a limit of detection of 10 HIV-1 RNA copies visualized by eye using a lateral flow immunoassay. To demonstrate automated sample-to-answer detection of HIV, we incorporate dried amplification reagents and wax valves in low-cost substrates with resistive heating elements and circuitry. By combining controlled heating with papers capillary flow, our assembled device automatically isolates viral particles from human blood samples, amplifies HIV-1 RNA, and transports products to a detection zone. We determine that as few as 105 HIV-1 viral particles can be separated from whole blood, amplified, and visually detected within 90 minutes of sample addition into our Microfluidic Rapid and Autonomous Analysis Device (microRAAD). The low-cost and automated attributes of microRAAD demonstrate its utility as a point-of-care testing platform.