Quantum dots: a new tool for anti-malarial drug assays

• Published in: Malaria Journal
• Main Authors: Ryu Jiyoung, Moraes Carolina B, Choi Youngseon, Dossin Fernando M, Ku Min-Je, Song Rita, Freitas-Junior Lucio H
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2011
• Subjects: Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/1475-2875-10-118; https://doaj.org/article/daac58a8c406489281a7a0566b1267f8

Abstract Background Malaria infects over 300 million people every year and one of the major obstacles for the eradication of the disease is parasite's resistance to current chemotherapy, thus new drugs are urgently needed. Quantum dot (QD) is a fluorescent nanocrystal that has been in the spotlight as a robust tool for visualization of live cell processes in real time. Here, a simple and efficient method using QD to directly label Plasmodium falciparum -infected erythrocytes (iRBCs) was searched in order to use the QD as a probe in an anti-malarial drug-screening assay. Methods A range of QDs with different chemical coatings were tested for their ability to specifically bind iRBCs by immunofluorescence assay (IFA). One QD was selected and used to detect parasite growth and drug sensitivity by flow cytometry. Results PEGylated-cationic QD (PCQD) was found to specifically label infected erythrocytes preferentially with late stage parasites. The detection of QD-labelled infected erythrocytes by flow cytometry was sensitive enough to monitor chloroquine anti-malarial toxicity with a drug incubation period as short as 24 h (EC 50 = 113nM). A comparison of our assay with another widely used anti-malarial drug screening assay, the pLDH assay, showed that PCQD-based assay had 50% improved sensitivity in detecting drug efficacy within a parasite life cycle. An excellent Z-factor of 0.8 shows that the QD assay is suitable for high-throughput screening. Conclusions This new assay can offer a rapid and robust platform to screen novel classes of anti-malarial drugs.