Magneto Immunoassays for Plasmodium falciparum Histidine-Rich Protein 2 Related to Malaria based on Magnetic Nanoparticles

Abstract

Magneto immunoassay-based strategies for the detection of Plasmodium falciparum histidine-rich protein 2 (HRP2) related to malaria are described for the first time by using magnetic micro- and nanoparticles. The covalent immobilization of a commercial monoclonal antibody toward the HRP2 protein in magnetic beads and nanoparticles was evaluated and compared. The immunological reaction for the protein HRP2 was successfully performed in a sandwich assay on magnetic micro- and nanoparticles by using a second monoclonal antibody labeled with the enzyme, horseradish peroxidase (HRP). Then, the modified magnetic particles were easily captured by a magneto sensor made of graphite-epoxy composite (m-GEC) which was also used as the transducer for the electrochemical detection. The performance of the immunoassay-based strategy with the electrochemical magneto immunosensors was successfully evaluated and compared with a novel magneto-ELISA based on optical detection using spiked serum samples. Improved sensitivity was obtained when using 300 nm magnetic nanoparticles in both cases. The electrochemical magneto immunosensor coupled with magnetic nanoparticles have shown better analytical performance in terms of limit of detection (0.36 ng mL(-1)), which is much lower than the LOD reported by other methods. Moreover, at a low level of HRP2 concentration of 31.0 ng mL(-1), a signal of 15.30 μA was reached with a cutoff value of 0.34 μA, giving a clear positive result with a non-specific adsorption ratio of 51. Due to the high sensitivity, this novel strategy offers great promise for rapid, simple, cost-effective, and on-site detection of falciparum malaria disease in patients, but also to screen out at-risk blood samples for prevention of transfusion-transmitted malaria.

A Novel Carbon Nanofibers Grown on Glass Microballoons Immunosensor: A Tool for Early Diagnosis of Malaria

“…The lowest detection limit of Pf HRP-2 reported in the literature to date using immunoassay technique has been 0.36 ng/mL [34]. The ultra-low visual detection limit of 0.025 ng/mL obtained from this study is attributed to the following.…”

Simultaneous capture and sequential detection of two malarial biomarkers on magnetic microparticles

“…Further, we have optimized the p LDH portion of the SCSD ELISA such that it can detect p LDH for both P. falciparum and P. vivax . For Pf HRPII, Castilho et al developed an immunomagnetic detection strategy in which a sandwich complex was formed on the surface of magnetic micro- or nanoparticles [21]. Electrochemical and optical detection strategies were used, and the limit of detection was found to be 12 pM, an order of magnitude higher than the dual on-bead SCSD developed herein.…”

Evaluation of a Novel Magneto-Optical Method for the Detection of Malaria Parasites

“…More recently, new techniques have emerged, which directly use hemozoin as target material for magnetic diagnosis. These techniques include detection of depolarized side-scatter in flow cytometry [37], electrochemical magneto immunoassays [38], magnetically enriched surface enhanced resonance Raman spectroscopy [39], [40], acousto-optic detection [31] and magneto-optical detection using polarized light [17], [18], [41]. Among them, to the best of our knowledge, our rotating crystal MO diagnostic technique is the first realized in a cost-effective and compact format with excellent sensitivity.…”