Stimuli-Responsive Polymer-Antibody Conjugates for Rapid Flow Through HIV-1 Diagnosis in Low-Resource Settings

According to the World Health Organization, over 22 million people in sub-Saharan Africa are infected with HIV. The availability of rapid, portable, and accurate point-of-care clinical diagnostic devices are needed to provide health care professionals with timely information to make decisions, monitor the spread of disease, and commence treatment. Polymerase chain reaction and conventional immunoassay remain the best diagnostic approach for screening and monitoring HIV; however, these techniques are expensive, laborious, and time consuming. Developing countries have limited resources to reduce transmission rates.   This has led to low patient return rates at public-sector testing sites to receive results (~31%) thus delaying decision making by clinicians. We present a less expensive and rapid flow through immunoassay diagnostics system mediated by capture of temperature-responsive polymer-antibody conjugates on heated porous membranes.  This system uses the bioconjugates to achieve binding in solution prior to downstream capture facilitated by aggregation of immunocomplexes on heated membrane surfaces. This system was optimized to provide two step immunocomplex capture and detection for application to HIV-1 p24 antigen. The flow-through assay can detect 10 pg/ml of p24 antigen using 25 µl 50% human plasma samples with ≤ 10% coefficient of variation.  The assay provide results in less than 20 minutes while achieving analytical sensitivity ranges similar to FDA approved p24 ELISA (Perkin Elmer). The Findings above substantiate the creation of a novel, affordable, and sensitive immunoassay system with reduced diagnostics time that will improve the screening and monitoring of HIV patients in low resource settings.