A discrete dielectrophoresis device for the separation of malaria‐infected cells

Abstract

Malaria is a serious disease caused by Plasmodium parasites that infect red blood cells (RBCs). This paper presents the continuous separation of malaria‐infected RBCs (iRBCs) from normal blood cells. The proposed method employed the discrete dielectrophoresis (DEP) in a microfluidic device with interdigitated electrodes. Our aim is to treat a sample having high concentration of cells to realize high throughput and to prevent the clogging of the microchannel with the use of the discrete DEP. The discrete DEP force for deflecting cells in the device was controlled by adjusting the magnitude, frequency, and duty cycle of the applied voltage. The effectiveness of the proposed method was demonstrated by separating the malaria‐infected cells in samples having a cell concentration of 106 cells/µl. From experimental results, we determined the enrichment that is needed to enhance the detection in the case of low parasitemia. The enrichment of the infected cells at the device output was 3000 times as high as that of the input containing 1 infected cell to 106 normal cells. Therefore, the proposed method is highly effective and can significantly facilitate the detection of the infected cells for the identification of Malaria patients.

Study on the dielectrophoretic characteristics of malaria‐infected red blood cells

“…On the other hand, f c2 of iRBCs is more or less the same as that of the normal red blood cells. The tendency of the change in f c1 of the infected cells agrees with previous results using interdigitated electrodes [27]. It is also worth noting that for the infected cells, few cells did not exhibit the crossover frequency f c2 up to 80 MHz, which was the limit of our instrument.…”

“…For red blood cells suspended in a low conductivity medium, they show two crossover frequencies of the DEP at which DEP switches between pDEP and nDEP in a low-frequency range (<1 MHz) and high-frequency region (>1 MHz). A few studies have been reported on the effect of the malaria infection on the crossover frequencies [25][26][27][28]. However, the DEP behavior of the malaria-infected cells is still not fully conclusive, in particular at high frequencies where the effect of cytoplasmic conductivity is prominent.…”

Low‐cost, high‐throughput and rapid‐prototyped 3D‐integrated dielectrophoretic channels for continuous cell enrichment and separation

“…Various methods have been developed to overcome these limitations, in particular in the development of 'continuous mode' separation whereby cell mixtures are continually sorted by DEP into different outlet channels, preventing the trap-filling associated with batch-mode sorters. However, most attempts generally have low flow rates [18][19][20] through the manufacture of electrodes that extend across the height of a (much taller) channel. There are different approaches to such '3D' electrodes; many groups use insulator-based structures (iDEP) [21][22][23], whereas others use the more conventional microelectrodebased structures, using variations on planar manufacture to form vertical columns that generate fields across the inter-electrode space [24,25].…”

Circadian rhythmicity in murine blood: Electrical effects of malaria infection and anemia

“…Malaria-infected RBCs exhibit changes to the RBC membrane and cytoplasm. The electrical properties of RBCs before and after infection with Plasmodium falciparum are a function of medium conductivity ( Gascoyne et al, 1997 ; Panklang et al, 2022 ), and membrane conductivity is associated with changes to membrane potential ( Rijo-Ferreira et al, 2020 ). Furthermore, quinine, a long used antimalarial drug, is a K + -channel blocker and alters the electrical conductivity of the cytoplasm ( Duncan et al, 2007 ).…”