UC Irvine

Global surveillance by the World Health Organization (WHO) has indicated a large stagnancy over the past few years in global efforts to eliminate malaria. Limited access to health care and proper diagnosis for endemic populations were emphasized as factors that attribute to such high morbidity and mortality rates. Rapid diagnostics tests (RDTs) have been reported to mitigate these factors, as well as other contributors to disease prevalence. The purpose of this thesis is to further demonstrate the feasibility of developing a quantitative, label-free RDT for disease biomarkers. The scope of this study is limited to the detection of plasmodium lactate dehydrogenase (pLDH) by electrochemical impedance spectroscopy (EIS) analysis of aptamer-protein complex formation as self-assembling monolayers (SAMs) on gold interdigitated electrodes (IDE). Notably, a Wheatstone bridge is integrated into the sensor design, improving system stability for accurate detection of pLDH in low concentrations. This demonstrates the feasibility of salivary detection of Plasmodium falciparum as a noninvasive method of malaria detection, which is especially important for addressing the needs of children in developing countries, who encompass a large portion of the global endemic population. To demonstrate [portability and cost-effectiveness, simple hardware was implemented in the design of this device. Together, the biosensor and hardware are designed to innovatively detect the charge transfer resistance (RCT) of an electrified interface as a simple impedance difference without the high costs and complexities of modern EIS instrumentation. The frequency domain of three different sensor designs will be analyzed for sensor optimization.