Surface tension driven flow of blood in a rectangular microfluidic channel: Effect of erythrocyte aggregation

Abstract

Microfluidic platforms have increasingly been explored for in vitro blood diagnostics and for studying complex microvascular processes. The perfusion of blood in such devices is typically achieved through pressure driven setups. Surface tension driven blood flow provides an alternative flow delivery option, and various studies in the literature have examined the behaviour of blood flow in such fluidic devices. In such flows, the influence of red blood cell (RBC) aggregation, the phenomenon majorly responsible for the non-Newtonian nature of blood, requires particular attention. In the present work, we examine differences in the surface tension driven flow of aggregating, non-aggregating RBC, and Newtonian suspensions, in a rectangular micro channel. The velocity fields were obtained using micro-PIV techniques. The analytical solution for blood velocity in the channel is developed utilising the power law model for blood viscosity. The results showed that RBC aggregation has an impact at the late stages of the flow, observed mainly in the bluntness of the velocity profiles. At the initial stages of the flow the shearing conditions are found moderately elevated, preventing intense RBC aggregate formation. As the flow decelerates in the channel RBC aggregation increases, affecting the flow characteristics.

Microfluidics Approach to the Mechanical Properties of Red Blood Cell Membrane and Their Effect on Blood Rheology

“…Therefore, if aggregation increases, then blood viscosity increases as well and the shear-thinning behavior of blood is altered. Numerical studies have demonstrated the effects of aggregation in blood viscosity [120,122,[152][153][154] and experimental studies have observed that RBCs' deformability induces cell aggregation during flow in microcapillaries, allowing the formation of clusters of cells [98,155,156]. Moreover, the aging of storaged RBCs also contributes to the increase in aggregation and affects its viscosity.…”

“…Eventually, high-speed and high-resolution cameras, with an enhanced sensitivity and mounted to an optical microscope, enabled velocity measurements of such small-scale flows. In this aspect, several techniques have been developed to measure the velocity fields of blood and RBCs at the microscale, such as µPIV (microparticles image velocimetry) or PTV (particle tracking velocimetry) and wavelet-based optical flow velocimetry (wOFV) [95][96][97][98][99]. 5), is averaged for different initial conditions of the RBC.…”

Assessment of Blood Biophysical Properties Using Pressure Sensing with Micropump and Microfluidic Comparator

“…These alterations contribute to a reduction of mass transport and interrupt the blood flow in capillary vessels. To effectively detect changes in blood samples from a physical point of view, several rheological properties (i.e., viscosity [ 3 , 4 , 5 , 6 ], viscoelasticity [ 7 ], red blood cell (RBC) deformability [ 8 , 9 , 10 , 11 , 12 , 13 ], RBC aggregation [ 14 , 15 , 16 , 17 ], RBC sedimentation rate [ 18 , 19 ], and Hct [ 20 ]) have been measured for screening or diagnosing various diseases, including coronary heart disease, hypertension, diabetes [ 21 ], sickle cell anemia [ 22 , 23 ], and malaria. Plasma protein (i.e., fibrinogen) contributes to increasing RBC aggregation.…”

“…Although a blood flow rate can be estimated consistently with micro-particle image velocimetry (PIV) [ 31 ], it is very difficult to obtain an accurate flow rate of a blood sample. The flow rate obtained with micro-PIV varies strongly with several factors, such as flow rate, hematocrit, diluent, RBC aggregation, and RBC deformability [ 13 , 14 , 29 ]. Whenever blood viscosity is to be monitored, tedious calibration procedures are required in advance using the same blood sample.…”

Development of an Optical Method for the Evaluation of Whole Blood Coagulation

“…Methods such as image segmentation allow the identification of structures with specific characteristics [ 25 , 26 ]. To accommodate the blood sample to be processed, simple microfluidic configurations are often used, offering several advantages [ 27 , 28 , 29 , 30 ]. Other techniques, such piezocoagulography, have been also utilized for blood coagulation, showing also the possibility of studying the initial stage of fibrin formation in the clotting process [ 31 ].…”