HIV: Helping Save Lives Through Early Diagnosis

Globally, HIV/AIDS claims more than two million lives each year. Further, the widespread co-infection of HIV with HBV and syphilis alters the clinical presentation with fatal consequences. Timely effective monitoring of people with HIV is crucial both in preventing those infected from developing AIDS and in limiting onward transmissions. Currently however, HIV diagnostic tools are limited to single marker detections, laboratorybased, require the input of skilled clinical personnel and are not suitable for transportation to resource limited regions – regions where infection rates are often at their highest. There is a driving need to develop new pointof-care (POC) technologies for early diagnosis and smart patient monitoring. Directly relevant to this objective, we are developing an affordable multi-functional, real-time handheld device, similar to glucose sensor, which is capable of detecting viral multiple markers from small sample volumes (e.g. a drop of blood). This approach enhances the specificity and the accuracy of early diagnosis and with the precise administration of antiretroviral drugs, HIV can be managed sustainably. Our POC prototype is based on Multi-marker Cantilever Nanosensors platform that integrates sample sorting (nanopillars) and surface capture chemistries. This technology offers many opportunities for direct detection of proteins such as antigens and antibodies against infectious organisms and potentially for the direct detection of organisms themselves without the need for labelling. Nanopillars acts as microfluidic sieve to separate and concentrate different markers of infection from clinical samples which are present in low copies. The antigens are detected and quantified by flowing across an array of cantilever nanosensors functionalised with carefully selected high affinity capture molecules raised against different (sub) types of HIV virions. Subsequently, the specific biomolecular binding event is translated into a nanomechanical signal analysed by the interference pattern created when they are illuminated by a laser. Here we find the sensor geometry and receptor chemistry are key to the limit of HIV multiple marker detection particularly in the regimens that allow for early diagnosis. We show that the cantilever arrays have the potential for highthroughput multi-target screening and are amenable for large scale production of compact, portable POC device to be used anywhere in the world.