Magnetic separation of malaria-infected red blood cells in various developmental stages.

Abstract

Malaria is a serious disease that threatens the public health, especially in developing countries. Various methods have been developed to separate malaria-infected red blood cells (i-RBCs) from blood samples for clinical diagnosis and biological and epidemiological research. In this study, we propose a simple and label-free method for separating not only late-stage but also early-stage i-RBCs on the basis of their paramagnetic characteristics due to the malaria byproduct, hemozoin, by using a magnetic field gradient. A polydimethylsiloxane (PDMS) microfluidic channel was fabricated and integrated with a ferromagnetic wire fixed on a glass slide. To evaluate the performance of the microfluidic device containing the ferromagnetic wire, lateral displacement of NaNO2-treated RBCs, which also have paramagnetic characteristics, was observed at various flow rates. The results showed excellent agreement with theoretically predicted values. The same device was applied to separate i-RBCs. Late-stage i-RBCs (trophozoites and schizonts), which contain optically visible black dots, were separated with a recovery rate of approximately 98.3%. In addition, using an optimal flow rate, early-stage (ring-stage) i-RBCs, which had been difficult to separate because of their low paramagnetic characteristics, were successfully separated with a recovery rate of 73%. The present technique, using permanent magnets and ferromagnetic wire in a microchannel, can effectively separate i-RBCs in various developmental stages so that it could provide a potential tool for studying the invasion mechanism of the malarial parasite, as well as performing antimalarial drug assays.

• Authors: Jeonghun Nam, Hui Huang, Hyunjung Lim, Chaeseung Lim, Sehyun Shin
• Journal: Analytical chemistry (Anal Chem) Vol. 85 Issue 15 Pg. 7316-23 (Aug 06 2013) ISSN: 1520-6882 [Electronic] United States
• PMID: 23815099 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Dimethylpolysiloxanes
• Hemeproteins
• hemozoin
• baysilon

Topics

• Cell Separation (instrumentation, methods)
• Dimethylpolysiloxanes (chemistry)
• Equipment Design
• Erythrocytes (cytology, parasitology)
• Hemeproteins (analysis)
• Magnetic Phenomena
• Malaria, Falciparum (parasitology)
• Microfluidic Analytical Techniques (instrumentation, methods)
• Plasmodium falciparum (physiology)
• Time Factors