Modeling of micropipette aspiration and optical tweezers stretching of erythrocytes with or without Malaria parasite

Guyue Jiao, Ruojing Zhang
2013 Theoretical and Applied Mechanics Letters  
The erythrocytes play an important role in the human body. The healthy erythrocytes can undergo extremely large deformation while passing through small capillaries. Their infection by Malaria Plasmodium falcipurum (P.f.) will lead to capillary blockage and blood flow obstruction. Many experimental and computational methods have been applied to study the increase in stickiness and decrease in deformability of the Malaria (P.f.) infected erythrocytes. The novelty of this paper lies in the
more » ... hment of an multi-component model for investigating mechanical properties of Malaria (P.f.) infected erythrocytes, especially of their enclosed parasites. Finite element method was applied to simulate the erythrocytes' deformation in micropipette aspiration and optical tweezers stretching using the computational software ABAQUS. The comparisons between simulations and experiments were able to quantitatively conclude the effects of stiffness and stickiness of the parasitophorous vacuole membrane on the cells' deformation, which could not be obtained from experiments directly. Malaria is a life-threatening tropical parasitic human disease transmitted by the female Anopheles mosquitoes. Data from 106 Malaria-endemic countries and territories reported that about 3.3 billion people were at the risk of Malaria in 2010. 1 Malaria is induced by a one-cell parasite called the Plasmodium. Human red blood cells (RBCs), also called erythrocytes can be infected by four different species of the Plasmodium (P.): P. falciparum (P.f. ), P. ovale, P. malariae and P. vivax. Among them, P. vivax and (P.f.) are the most common species, but the malaria induced by the latter is the most dangerous due to its ability to cause cerebral malaria. 2 Healthy erythrocytes are shaped like a biconcave disk under static and isotonic condition. They are filled with hemoglobin, but do not have a nucleus or cytoplasmic organelles. A human erythrocyte membrane consists of transmembrane proteins, lipid bilayer and the underlying spectrin network. 3 After parasite invasion, the host erythrocyte undergoes 3 stages of severe structural changes. 4 In its ring stage, the parasitophorous vacuole (PV) encloses the parasites, forming a ringlike structure. The parasitophorous vacuole membrane (PVM) is semi-permeable which allows the acquisition of nutrient and the secretion of parasite. At about 5-20 h after parasite invasion, which is called the trophozoite stage, the parasites continue growing and occupy nearly 40% of the host cell's volume. In the last stage which is called schizont stage, the parasite divides itself and forms 16-32 daughter merozoites surrounded by the PVM. These daughter merozoites will burst out and invade uninfected erythrocytes. a) Corresponding author.
doi:10.1063/2.1303401 fatcat:sjc6izppwnajdepvpevympw4ze