Viscosity of blood at the microscale infected by Plasmodium falciparum

Abstract

The viscosity of blood infected by malaria is studied using a microfluidic-based rheometer. Malaria is an infectious disease that causes numerous infectious worldwide, being one of the most prevalent diseases. The findings provide insights into the physical properties of the parasite, with potential implications for malaria diagnostics. The microrheometer allows to perform experiments and obtain the viscosity curve as a function of the shear rate using low volumes of blood, contrary to commercial viscosimeters. The viscosity of blood is well characterized using a power-law model, which only needs two parameters to be defined. Blood samples in culture media (RPMI) and at a physiological temperature were analysed. Moreover, blood samples infected with Plasmodium falciparum with different percentage of infected red blood cells were analyzed. Results show a shift towards a Newtonian behaviour as parasitemia increased, losing the characteristic shear-thinning behaviour of blood. This study also examines the influence of mature parasite stages on blood viscosity, revealing their contribution to the observed changes. These findings have two implications. Firstly, we enhance our understanding of the rheological alterations caused by malaria infection, which can aid in developing improved diagnostic tools based on rheological markers. Secondly, the surprising results obtained contribute to the knowledge about the effects of the parasite as the sample ages at 37◦C, which ultimately could aid the development of new malaria treatment techniques.