Spatially multiplexed biogel nanosensors with boron-doped diamond microelectrode arrays for HIV self-testing - Project Summary The clinical studies demonstrating that when people maintain undetectable levels of viral loads, HIV cannot transmit provided an exciting new direction for HIV management. A central part of HIV health care will be to develop the technology required for home testing of HIV viral loads similar to diabetes management. There are several requirements for such a home test. First, sample preparation of virus must cleanly isolate virus-laden plasma without lysing white blood cells or require any lab equipment. Second, the test must store reagents on- chip at ambient conditions over long periods. Third, the test must provide accurate and ideally, semi-quantitative information without requiring extensive manipulation, training, or expensive instrumentation. Current diagnostics cannot meet these requirements. The highest value test is nucleic acid amplification but the enzymes and buffers require cold chain storage, trained personnel, and frequently, fluorescence-based instrumentation. Antibody- based tests for viral capture on lateral flow are hampered by lower analytical sensitivity and specificity values, are not quantitative, and are hampered by protein rather than nucleic acid-based manufacturing infrastructures. Here we propose the integration of our novel biogel nanosensors and boron-doped diamond microelectrode arrays to directly provide actionable, semi-quantitative, HIV viral load information for the home user. Our hydrogel encapsulates and locks in NAAT tests in aqueous environments without oil or manufacturing additional compartments. The gel provides safe, on-chip storage of reagents and critically, is printable for rapid fabrication of arrays for digital quantitation. The gel is also specifically positively charged to attract and concentrate viral genomes from the raw sample which would improve the LOD95. In our proposed platform, a boron-doped diamond microelectrode underlies each spot in the array. This will provide an individual, electrochemical readout for every spot which can be interpreted in a digital format for potential quantification. With this platform, the user simply adds blood from a fingerstick and uses a membrane to separate out the plasma. A second wicking membrane with lysis reagents delivers viral genomes to the biogel nanosensor array via lateral flow. Together, the ease of use, on-chip storage, creation of a digital electrochemical readout, and compatibility with manufacturing infrastructures to keep costs low yields a promising, viable platform for HIV management at home.
