Towards a smartphone-connected point-of-care test for HIV

• Main Author: Turbe, V.
• Other Authors: McKendry, R. M.
• Published: University College London (University of London) 2017
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.746487

The devastation caused by HIV is driving the development of new point-of-care diagnostics. The work presented in this thesis aims to help develop a new generation of smartphone- connected HIV tests designed to address the very high levels of undiagnosed HIV-infected individuals, by widening access to HIV testing to doctors surgeries, pharmacies and developing countries. The biosensor is based on mass manufacturable surface acoustic wave (SAW) devices, and uses piezoelectricity to transduce the binding of biomarkers on the surface of the device into a measurable electric signal, making the test low cost, easy to use and reliable. In addition, the SAW biosensor presented here has the ability to wirelessly and securely transmit results to healthcare providers to potentially offer follow-up appointments at local clinics, or virtually. This thesis begins with the theory behind SAW biosensors. A more focussed characterisation of the specific device developed is then presented, followed by the details of the work done to optimise the biosensor in order to make it a good candidate for a point-of-care test for HIV. Key results include the proof of concept detection of different biomarkers of HIV infection, as well as a demonstration of the ability of the SAW biosensor to deliver a fast response. Different pilot studies are then presented, demonstrating the performance of the device as a diagnostic test, highlighting 100% sensitivity and 100% specificity. These were conducted with more than 30 confirmed HIV positive patient samples and more than 100 healthy volunteers. The following chapter then examines the fundamental mechanisms underpinning the SAW biosensor output and an empirical method to ultimately design more sensitive devices in future antigen detection. This thesis concludes with a summary of the main results and future work, including the potential for larger clinical studies, and field trials in developing countries.