Article pubs.acs.org/acssensors
Integrated Magnetic Bead−Quantum Dot Immunoassay for Malaria Detection Chloe Kim,† Gwendolyn Hoffmann,† and Peter C. Searson*,† †
Department of Materials Science and Engineering and Institute for Nanobiotechnology, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States S Supporting Information *
ABSTRACT: Malaria persists as a disease of high morbidity and mortality due to improper diagnosis, overuse of drugs, rapidly evolving drug resistant parasites, and poor disease monitoring. The two common tests used in developing countries, microscopic examination of Glemsa slides and rapid diagnostic tests (RDTs), have limitations associated with variability in specificity and sensitivity, and qualitative outcome. Here we report on an immunoassay using magnetic beads for capture and quantum dots for detection of histidine-rich protein 2 (HRP2). Conventional immunoassays, such as ELISA, and molecular analysis tools, such as PCR, are difficult to implement in low resource settings. Therefore, to provide a proof-ofprinciple of translation of this assay to low resource settings, we demonstrate HRP2 detection in an automated droplet-based microfluidic device. Droplet-based platforms have the potential to allow translation of molecular detection assays to point-of-care use in low resource settings. KEYWORDS: malaria, histidine-rich protein 2, immunoassay, droplet assay, magnetic beads
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and many individuals can be screened in a short period of time. The sensitivity of RDTs is in the range of 100−200 parasites μL−1 of blood.10,11,13,14 The major limitations of current RDTs are the variability in specificity, the lack of quality control, and the fact that results are binary (positive/negative). Also, the sensitivity of RDTs decreases at a low concentration (
