Integrated Magnetic Bead–Quantum Dot Immunoassay for Malaria Detection

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-of-principle 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.

(Bio)conjugation Strategies Applied to Fluorescent Semiconductor Quantum Dots

“…Another issue for this strategy is the presence of amino groups in biological systems, which could lead to an undesired link between the nanoparticle and its target. 43 Aminated QDs have been conjugated, using these homobifunctional coupling agents, to peptides and proteins, 72,73 lectins, 74 antibodies, [75][76][77] receptor ligands 78 and nucleic acids. 79 Ruan et al 73 employed CdSe/ZnS QDs as fluorescentlabeling probes to target the phosphatidylserine exposed in the plasma membrane, due to drug-induced apoptosis.…”

The review of Lab‐on‐PCB for biomedical application

“…In addition, the flexibility of the PCB circuit can also bring more convenience to immunoassay devices. For example, Kim et al used a PCB-based electromagnetic coil array to create a "pipelined" immunodetection device to detect malaria [79]. As shown in Fig.…”

“…The process of immunoassay of malaria which can perform in "pipelined" mode under the control of PCB circuit, reprinted with permission from[79]. Copyright 2017 American Chemical Society.…”

Simple, rapid, and accurate malaria diagnostic platform using microfluidic-based immunoassay of Plasmodium falciparum lactate dehydrogenase

“…Although the microscopic examination is the gold standard for malaria diagnosis and is rapid and cost-effective, it requires highly trained personnel. Meanwhile, the RDT, a lateral flow immunoassay, is a useful method in low-resource environments because it is possible to provide cost-effective, [5,20]. However, RDTs have sensitivity limitations, such as the inability to detect < 200 parasites/µL or < 1 ng/mL [16,19,21,22].…”

“…Additionally, they developed a simultaneous capture and sequential detection of two malarial biomarkers (PfLDH and HRP2) on magnetic microparticles [23]. Kim et al detected HRP2 up to 0.1 ng/mL using antibody-immobilized magnetic beads and quantum dots using an automated dropletbased microfluidic device [20]. Although these studies were developed to overcome the limitations of conventional enzyme-linked immunosorbent assay (ELISA), nanoparticle-based immunoassays still require a relatively complex surface functionalization process and a large amount of antibody to immobilize the antibody.…”