The Application of Biomedical Engineering Techniques to the Diagnosis and Management of Tropical Diseases: A Review <s> Microarray Chip <s> Antigen-specific human monoclonal antibodies (mAbs) are key candidates for therapeutic agents. However, the availability of a suitable screening system for antigen-specific antibody-secreting cells (ASCs) is limited in humans. Here we present a unique method for detecting individual ASCs using microwell array chips, which enables the analysis of live cells on a single-cell basis and offers a rapid, efficient and high-throughput (up to 234,000 individual cells) system for identifying and recovering objective ASCs. We applied the system to detect and retrieve ASCs for hepatitis B virus and influenza viruses from human peripheral blood lymphocytes and produced human mAbs with virus-neutralizing activities within a week. Furthermore, we show that the system is useful for detecting ASCs for multiple antigens as well as for selection of ASCs secreting high-affinity antibodies on a chip. Our method can open the way for the generation of therapeutic antibodies for individual patients. <s> BIB001 </s> The Application of Biomedical Engineering Techniques to the Diagnosis and Management of Tropical Diseases: A Review <s> Microarray Chip <s> Background ::: Malaria is one of the major human infectious diseases in many endemic countries. For prevention of the spread of malaria, it is necessary to develop an early, sensitive, accurate and conventional diagnosis system. ::: ::: ::: Methods and Findings ::: A cell microarray chip was used to detect for malaria-infected erythrocytes. The chip, with 20,944 microchambers (105 µm width and 50 µm depth), was made from polystyrene, and the formation of monolayers of erythrocytes in the microchambers was observed. Cultured Plasmodium falciparum strain 3D7 was used to examine the potential of the cell microarray chip for malaria diagnosis. An erythrocyte suspension in a nuclear staining dye, SYTO 59, was dispersed on the chip surface, followed by 10 min standing to allow the erythrocytes to settle down into the microchambers. About 130 erythrocytes were accommodated in each microchamber, there being over 2,700,000 erythrocytes in total on a chip. A microarray scanner was employed to detect any fluorescence-positive erythrocytes within 5 min, and 0.0001% parasitemia could be detected. To examine the contamination by leukocytes of purified erythrocytes from human blood, 20 µl of whole blood was mixed with 10 ml of RPMI 1640, and the mixture was passed through a leukocyte isolation filter. The eluted portion was centrifuged at 1,000×g for 2 min, and the pellet was dispersed in 1.0 ml of medium. SYTO 59 was added to the erythrocyte suspension, followed by analysis on a cell microarray chip. Similar accommodation of cells in the microchambers was observed. The number of contaminating leukocytes was less than 1 on a cell microarray chip. ::: ::: ::: Conclusion ::: The potential of the cell microarray chip for the detection of malaria-infected erythrocytes was shown, it offering 10–100 times higher sensitivity than that of conventional light microscopy and easy operation in 15 min with purified erythrocytes. <s> BIB002
Recently, Jin et al. BIB001 proposed a microwell array chip that enables the analysis of single live cells. The proposed system is capable to analyze more than 234,000 individual cells rapidly and efficiently. Expanding on the work of Jin et al. BIB001 , Yatsushiro et al. BIB002 reported a novel high-throughput screening and analysis system for malaria infection using microarray chip with a laser scanner (Figure 8 ). They utilized a polystyrene chip that contains 20,944 micro-chambers fabricated using molding techniques. The author claimed that the system is 10 to 100 times more sensitive than the conventional light microscopy diagnosis method. This system requires 15 min to detect malaria parasites in erythrocytes extracted from centrifuged blood.