"LLISA:'Liposome-Linked Immunosorbant Assay' for Detection of HIV Viral Load at Point-of-Care"

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DESCRIPTION (provided by applicant): HIV/AIDS affects more than 33 million people throughout the world, and is especially a critical problem in resource-poor regions in sub-Saharan Africa, where 67% of all HIV/AIDS patients live. Antiretroviral therapy (ART) increases the longevity and quality of life for HIV patients, and global efforts have increased the accessibility of such treatment by 30-fold in sub-Saharan Africa between 2003 and 2008. However, the lack of objective diagnostic tests to determine when to start ART and to monitor its success hinders the effective use of treatment. In addition to the counting of CD4+ T Lymphocytes, it is also highly desirable to perform viral load counts at the point-of-care, as both these parameters are needed for the development of the appropriate treatment strategy. HIV viruses could occur at levels ranging from 10pfu/¿l to thousands of pfu/¿l of whole blood, making it challenging to detect these minute quantities of particles. Current tests include both antibody- based and PCR-based and are not available at point-of-care, especially for resource-limited settings. It should be also pointed out that such devices would of course be extremely valuable also for the developed world, for remote settings, at bedside, or at the doctor's office for a range of applications in detection of viruses. As a solution to these problems presented above, micro-fabricated point-of-care (POC) biochips for HIV/AIDS analysis hold tremendous promise. We propose to develop an integrated device for the electrical detection of HIV viral load at point-of-care. We propose to build on our extensive preliminary work to develop electrically- based sensing methods within micro-fluidic biochips to greatly reduce the operating costs, increase portability, and provide simple-to-use diagnostic kits that can be operated by healthcare workers in remote facilities or during home visits. Our integrated approach is innovative as we will; (i) capture the specific viruses from whole blood, (ii) label these viruses using liposomes tagged with antibodies for the viral particles, (iii) lyse the liposomes by lowerin the electrical conductivity of the medium, and detect the changes in the electrical impedance of the medium in the microfluidic capture chamber. The change in impedance is expected to correlate to the number of virus particles captured. We plan to use VSV-G virus spiked in whole human blood as a model for HIV during this R21 to demonstrate the proof of concept of the novel detection scheme. The interdisciplinary collaboration brings together the expertise of the Co-PIs. We will build on the extensive work in Bashir group (UIUC) on development of microfluidic point-of-care tests that are electrically based, and in Lee Lab (UCI) in microfluidics and generation of liposomes of controlled size and properties. With the integration of these two sets of expertise, we expect to address the grand challenge of developing point-of-care viral load assays.