Rapid Detection of Malaria Antigen in Human Whole Blood using a Handheld Lab-On-Chip Device

Abstract

Malaria is a human infectious disease that affects around 250 million people each year. Primarily found in regions of Africa, Asia, and South America, malaria is typically caused by the protozoa Plasmodium falciparum, and results in symptoms ranging from high fever to death. The most common detection methods currently consist of ELISA, PCR, and blood film smears; however, each of these methods requires a full laboratory environment for proper utilization, with assay times ranging from 2-8 hours. In this study, a novel handheld detection device based on the properties of immunoagglutination will be modified to detect malaria in human whole blood through histidine-rich protein 2 (HRP-2), an antigen expressed only by P. falciparum. HRP-2 antibodies are covalently attached to 920 ?m carboxylated polystyrene nanoparticles, which are mixed with the target human whole blood in a lab-on-chip testing environment. Using a 640 nm LED and avalanche photodiode pair, the sample is illuminated and forward light scatter caused by immunoagglutination of the HRP-2 antigen to the antibodies present on the nanoparticles is measured. The final device is compact, battery powered, low-cost, and capable of detecting HRP-2 antigens in human whole blood with a detection limit of 1 pg/ml and an assay time of approximately 8 minutes. The device represents a significant improvement in assay time over current malaria detection methods at a relatively low cost.