Economic, logistical, and physical barriers limit HIV viral load quantification, the gold standard for HIV diagnostics. The cost of the test is high (approximately $100 per test) and the intricate equipment required limits testing to laboratories staffed by highly trained technicians. Also, the labile nature of the biomarker, viral RNA, require testing to be performed within 6 hours of blood draw unless the RNA can be stabilized, thus limiting the geographical reach of this test. Current point-of-care (POC) HIV tests rely on antibody titer, but this biomarker is limited in early, acute-stage infections, resulting in many false negatives. Additionally, strategies to preserve blood sample (e.g., dried blood spots) add additional steps to the workflow (e.g., spotting, drying, elution), resulting in added labor and increased potential for error. We propose a device that merges a novel blood collection method in commercial development by Tasso Inc., with a technology for sample preparation and stabilization developed at UW - Madison. Through a simple-to-use method integrating blood collection and sample preparation, the device will alleviate many of the barriers (time, cost, trained specialist) to the applications of HIV diagnostics. Further, a novel method for sample stabilization enables this method to be used and transported from any number of low-resource settings, expanding the reach of blood diagnostic methods. To achieve this project, Tasso is uniquely positioned through three key collaborations: 1) Professor David Beebe as an expert consultant for simple microfluidic devices for sample preparation with startup experience in 4 different companies, 2) Dr. Frank Graziano as an expert consultant for diagnostics for low-resource settings with a special affiliation with the Joint Clinical Research Centre (JCRC) in Uganda, and 3) the Morgridge Institutes for Research, enabling Tasso to have direct access to established prototyping facilities, along with access to experts in device design for manufacturability (including Thomas Mackie, founder of TomoTherapy). The proposal consists of three Aims. First, the Tasso device for blood acquisition will be modified for economically-limited deployment by making the non-blood contacting portion of the device reusable. Next, a one-step sample preparation cartridge, the SLIDE, will be optimized to extract viral RNA from blood samples collected with the Tasso device. Lastly, a wax-based sealing mechanism will be integrated into the SLIDE to enable on-chip reverse transcription, which stabilizes viral RNA into DNA, and sealing for transport. At the conclusion of Phase I, an integrated, optimized proof-of-concept platform will be capable of blood acquisition, viral RNA extraction, and RNA stabilization and storage. In Phase II, this prototype will be tested on patients with the assistance of consultant Dr. Frank Graziano, an expert in HIV- related clinical trials. Additionall, a nucleic acid amplification / quantitation component will be developed, enabling complete sample-to-answer operation and further mitigating barriers to HIV viral load testing access.
Currently, HIV viral load testing is inaccessible to large segments of the population due to economic barriers (test cost ? $100), physical barriers (viral RNA in unstable in blood, and thus cannot be transported long distances), and logistical barriers (sophisticated equipment is necessary to extract and quantify viral RNA). In this proposal, we aim to overcome these barriers through the development of a microfluid platform capable of performing streamlined and inexpensive acquisition, isolation, and stabilization of viral RNA at the point-of-care. We anticipate that this technology will reduce HIV viral load testing cost by greater than 50% and enhance accessibility of this critical diagnostic to significantly more people.
