Stage-Dependent Topographical and Optical Properties of Plasmodium Falciparum-Infected Red Blood Cells

Author(s): Katharina Preißinger, Petra Molnar, Beata Vertessy, Istvan Kezsmarki, Miklos Kellermayer

Addressing the challenge of efficient malaria treatment requires in-depth understanding of the parasite maturation during the intra- erythrocytic cycle. Exploring the structural and functional changes of the parasite through the intra-erythrocytic stages and their impact on red blood cells (RBCs) is a cornerstone of antimalarial drug development. In order to precisely trace such changes, we performed a thorough imaging study of RBCs infected by Plasmo-dium falciparum, by using atomic force microscopy (AFM) and total internal reflection fluorescence microscopy (TIRF), supplemented with bright field microscopy (BFM) for stage assignment. This multifaceted imaging approach allows to reveal structure–function relations via correlations of the parasite maturation with morphological and fluore-scence properties of the host RBCs. We established diagnostic patterns characteristic to the parasite stages based on the topographical profile of infected RBCs, which show close correlation with their TIRF map. Furthermore, we found that hemozoin crystals exhibit a strong optical contrast, possibly due to the quen-ching of fluorescence, which can be used to locate hemozoin crystals within the RBCs and following their growth.