Blood dynamics in microfabricated vessel networks
A.W. Mulivor, S. Shevkoplyas, C. Sun, M.W. Bitensky and L.L. Munn
Massachusetts General Hospital, US
microfludics, blood, erythrocyte, leukocyte, RBC, WBC, margination
Blood displays interesting behavior when flowing through channels with dimensions similar to the blood cells. Two well-known examples include the decrease in flow resistance with tube size (Fahraeus-Lindqvist effect) and the enhancement of leukocyte (WBC) adhesion in postcapillary venule expansions by erythrocytes (RBCs). Until recently, detailed mechanistic studies of such blood flow anomalies were difficult because of the lack of methodology to reproduce blood flow in artificial microvessels with realistic dimensions and complexity.
To overcome this limitation, we design and microfabricate networks of microchannels cast in a transparent silicone polymer (PDMS). We show that capillary to postcapillary transitions, branches and curved segments are capable of promoting leukocyte margination. Leukocytes in whole blood solutions marginated more quickly at low shear rates compared to high shear rates. The results indicate the average distance required for a leukocyte to marginate depends on the aggregation level and that normal human blood, with intermediate levels of RBC aggregation, has appropriate rheological properties to facilitate leukocyte margination.
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Nanotech 2006 Conference Program Abstract