Mechanical probing of malaria-infected erythrocytes

Abstract

One of the key features of the biology and pathophysiology of the Plasmodium malaria is enhanced rigidification of the infected red blood cell. Some proteins released from the parasite are believed to induce alterations of the membrane skeleton and mechanical properties of the red blood cell. Previous studies primarily used micropipette aspiration and laminar shear flow to probe cell deformability. In this work, optical tweezers was employed to obtain the first direct and continuous force-deformation responses from in-vitro stretching of various developmental stages of Plasmodium falciparum within red blood cells. The parasite was visualized using fluorescent labelling while the host red blood cell was being stretched by the optical tweezers. By combining three-dimensional computational simulations of stretch deformation, an order of magnitude increase in shear modulus was estimated in red blood cell infected by the schizont stage parasite. This optical tweezers approach may therefore offer a new framework to understand the link between alteration to mechanical characteristics of parasitized cells and disease state.