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Advisor(s)
Abstract(s)
The flow properties of blood in the microcirculation depend strongly on the hematocrit (Hct), microvessel
geometry, and cell properties. Previous in vitro studies have measured the radial displacement of red blood cells
(RBCs) at concentrated suspensions using conventional microscopes. However, to measure the RBCs motion
they used transparent suspensions of ghost red cells, which may have different physical properties than normal
RBCs. The present study introduces a new approach (confocal micro-PTV) to measure the motion of labeled
RBCs flowing in concentrated suspensions of normal RBCs. The ability of confocal systems to obtain thin infocus
planes allowed us to measure the radial position of individual RBCs accurately and to consequently
measure the interaction between multiple labeled RBCs. All the measurements were performed in the center
plane of both 50 mm and 100 mm glass capillaries at Reynolds numbers (Re) from 0.003 to 0.005 using Hcts
from 2 to 35%. To quantify the motion and interaction of multiple RBCs, we used the RBC radial dispersion
(Dyy). Our results clearly demonstrate that Dyy strongly depends on the Hct. The RBCs exhibited higher Dyy at
radial positions between 0.4 R and 0.8 R and lower Dyy at locations adjacent to the wall (0.8 R–1 R) and around
the middle of the capillary (0 R–0.2 R). The present work also demonstrates that Dyy tends to decrease with a
decrease in the diameter. The information provided by this study not only complements previous investigations
on microhemorheology of both dilute and concentrated suspensions of RBCs, but also shows the influence of
both Hct and geometry on the radial dispersion of RBCs. This information is important for a better
understanding of blood mass transport mechanisms under both physiological and pathological conditions.
Description
Keywords
Red blood cells Microchannels Microcirculation Blood flow Confocal micro-PTV RBC dispersion
Citation
Lima, R.; Ishikawa, T.; Imai, Y.; Takeda, M.; Wada, S.; Yamaguchi, T. (2008). Radial dispersion of red blood cells in blood flowing through glass capillaries: the role of hematocrit and geometry. Journal of Biomechanics. ISSN 0021-9290. 41:10, p.2188-2196
Publisher
Elsevier