Development of Rapid Immunoassays for Improved Point-of-Care Malaria Diagnostics

Abstract

Delivery of diagnostic tools to low-resource settings under the burden of the malaria epidemic faces numerous challenges. These underdeveloped areas are often characterized by poverty, absent or intermittent electricity, hot and humid environmental conditions as well as a lack of skilled clinicians. Rapid diagnostic tests (RDTs) were developed to circumvent these challenges in the form of a low-cost, rapid, easy to use test. Despite the many advantages of RDTs, the changing climate of infectious disease education, prevention, and treatment has brought to light the areas in which these tests can be improved to detect asymptomatic patients. This work outlines the development of two parallel assays for detection of asymptomatic malaria. First, Ni(II)NTA magnetic particles were employed to extract, purify, and concentrate the most common malarial biomarker, Plasmodium falciparum Histidine Rich Protein II (pfHRPII), from a blood sample, in less than 30 minutes. Application of this concentrated protein to commercially available RDTs afforded a 4-fold enhancement in performance, into the single parasite/µL detection regime. While integration of new sample preparation methods with existing technologies represents one approach toward infectious disease elimination, a unique, rapid immunomagnetic on-bead ELISA for pfHRPII detection was also developed, as an alternative strategy for malaria diagnosis. In less than 30 minutes, a full sandwich ELISA was complete for the detection of single parasites/µL. Effecting a change in low-resource diagnostics and global healthcare may not necessarily require a complete reworking of the system, but simply using innovation to make the existing constructs work better.