Microscale flow dynamics of red blood cells in microchannels: an experimental and numerical analysis

Approximately, the half volume of the blood is composed of red blood cells (RBCs) which is believed to strongly influence its flow properties. Blood flow in microvessels depends strongly on the motion, deformation and interaction of RBCs. Several experimental studies on both individual and concentrated RBCs have already been performed in the past (Goldsmith 1971, Goldsmith and Marlow 1979, Chien et al. 1984, Goldsmith and Turitto 1986). However, all studies used conventional microscopes and also ghost cells to obtain visible trace RBCs through the microchannel. Recently, considerable progress in the development of confocal microscopy and consequent advantages of this microscope over the conventional microscopes have led to a new technique known as confocal micro-PIV (Tanaami et al. 2002, Park et al. 2004, Lima et al. 2006, 2007a). This technique combines the conventional PIV system with a spinning disk confocal microscope (SDCM). Due to its outstanding spatial filtering technique together with the multiple point light illumination system, this technique has the ability to obtain in-focus images with optical thickness less than 1 mm. In a numerical context, blood flow in large arteries is usually modeled as a continuum however this assumption is not valid in small vessels such as arterioles and capillaries. In this way, we are developing an integrative multi-scale model to simulate the blood flow at mesoscopic level. This computational approach may provide important information on the rheology of blood in small vasculatures where non-Newtonian property of blood is not negligible. The main purpose of this paper is to measure flow behavior of individual RBCs at different haematocrits (Hct) through a 75mm circular polydimethysiloxane (PDMS) microchannel by means of confocal micro-PTV system. Moreover we introduce an integrative multi-scale model to simulate the blood flow behavior through microvessels in order to obtain more detailed insights about the blood rhelogical properties at cellular level.This study was supported in part by the following grants: International Doctoral Program in Engineering from the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT), “Revolutionary Simulation Software (RSS21)” next-generation IT program of MEXT; Grants-in-Aid for Scientific Research from MEXT and JSPS Scientific Research in Priority Areas (768) “Biomechanics at Micro- and Nanoscale Levels,” Scientific Research (A) No.16200031 “Mechanism of the formation, destruction, and movement of thrombi responsible for ischemia of vital organs”, Grant-in-Aid for Young Scientists (A) 19680024