Quantitative microfluidic NAT-on-USB: towards routine HIV viral load testing

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HIV, the virus that causes AIDS, continues to be a significant public health issue. Fortunately, HIV can be effectively managed if people of HIV can be identified and their virus is controlled to undetectable levels by antiretroviral therapy. Increasing access to routine viral load testing can help reduce the treatment failure rate by early detection of viral rebound caused by either drug resistance or poor therapy adherence. To this end, HIV self-testing, a process in which individual who wants to know HIV status collects a specimen, performs a test and interprets the result in private, has become an empowering and innovative approach. Existing HIV self-testing methods rely almost exclusively on lateral flow based test to detect host antibody response to HIV infection. They could miss a significant portion of asymptomatic individuals during the 6-12 weeks of early infection window; they also lack the ability for detection of viral rebound. Nucleic acid testing is currently the only method for viral load quantification. Nevertheless, its use by laypersons is limited due to the sample handling and assay complexity. The proposed research has the potential to significantly enhance the treatment outcomes for individuals of HIV under antiretroviral therapy. In addition, with educational and outreach activities, the proposed research is well positioned to enhance the integrative learning experience and to engage multidisciplinary students at many levels.The primary research objective of this proposal is to explore an ultra-compact quantitative nucleic acid testing (NAT) on a disposable microfluidic chip with a USB analyzer to detect HIV-1 viral rebound that is simple enough for laypersons to test themselves to monitor treatment adherence. The goal is to develop and validate a whole blood-based test that can semi-quantitatively assess the presence of HIV-1 RNA at cell concentrations as low as 1000 copies/ml. The test can be performed similarly to a home blood glucose test with a single step of finger-prick blood loading. To this end, four research tasks regarding the microfluidic sample preparation, amplification assay, USB analyzer integration, and analytical validation will be pursued. Task 1. Automated microfluidic sample preparation. A streamlined microfluidic chip for automated plasma separation and RNA extraction from whole blood will be developed. Task 2. An HIV-1 Real-time reverse transcription loop-mediated isothermal amplification assay will be optimized and the lowest possible limit of detection will be explored. Task 3. Analyzer integration and small-scale prototyping. The analyzer hardware and software will be developed and integrated for easy and robust operation. Task 4. Laboratory validation with control samples. The prototyped device will be validated in lab settings using HIV-1 plasma samples spiked into whole blood.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.