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Blood flow behavior in microchannels: past, current and future trends

Over the years, various experimental methods have been applied in an effort to understand the blood flow behavior in microcirculation. Most of our current knowledge in microcirculation is based on macroscopic flow phenomena such as Fahraeus effect and Fahraeus-Linqvist effect. The development of optical experimental techniques has contributed to obtain possible explanations on the way the blood flows through mi...

Micro-flow visualization of magnetic nanoparticles for biomedical applications

An investigation to measure the flow behavior of magnetic nanoparticles through a 100mm microchannel is conducted. The magnetic field is applied externally by a permanent magnet and by using a micro-PTV system it was possible to measure the flow behavior of magnetic nanoparticles at different flow rates and magnetic fields through a 100mm glass capillary. A strong dependence on both magnetic and hydrodynamic fo...

Flow visualization of trace particles and red blood cells in a microchannel wit...

This paper aims to investigate the effect of both diverging and converging bifurcations on the flow behaviour of pure water (PW) and red blood cells (RBCs). A confocal micro-PTV system is used to visualize and measure the flow characteristics of the working fluids. The results show no formation of a cell-free layer (CFL) around the apex of the bifurcation. In contrast, there is a clear formation of a triangular...

Asymmetry of red blood cell motions in a microchannel with a diverging and conv...

In microcirculation, red blood cells (RBCs) flowing through bifurcations may deform considerably due to combination of different phenomena that happen at the micro-scale level, such as: attraction effect, high shear and extensional stress, all of which may influence the rheological properties and flow behavior of blood. Thus, it is important to investigate in detail the behavior of blood flow occurring at both ...

Motions of trace particles and red blood cells in a PDMS microchannel with a co...

This paper presents microflow visualizations of both pure water and red blood cells (RBCs) in a converging bifurcation. The visualizations are a combination of results obtained from a confocal micro-PTV system and an image analysis technique known as “Zproject” from ImageJ. Our preliminary qualitative results suggest that the cell-free layer that is formed in middle of the microchannel (after confluence apex) m...

Micro-flow visualization of in vitro blood through a microchannel with a bifurc...

Determination of the cell-free layer in circular PDMS microchannels

In microcirculation the cell-free layer is believed to reduce the friction between red blood cells (RBCs) and endothelial cells and consequently reduce blood flow resistance. However, the complex formation of the cell-free layer has not yet been convincingly described mainly due to multi-physical and hemorheological factors that affect this phenomenon. In this experimental work, we study the effect of hematocri...

Confocal micro-flow visualization of blood cells

Progress in the development of confocal microscopy and the advantages of this technique over conventional microscopy have led to a new technique known as confocal micro-PTV. This technique combines a manual tracking method with a spinning disk confocal microscope. By combining its spatial filtering technique with a multipoint illumination system, this technique has the ability to obtain in-focus images with opt...

Red blood cell dispersion in 100 um glass capillaries: the temperature effect

The rheological behaviour of the red blood cells (RBCs) flowing in microvessels and microchannels depend on several effects, such as hematocrit (Hct), geometry, and temperature. Previous in vitro studies have measured the Hct effect on the radial dispersion (Dyy) at both diluted and concentrated suspensions of RBCs. However, according to our knowledge the effect of the temperature on RBC Dyy was never studied. ...

Micro-flow visualization of in vitro blood through a microchannel with a bifurc...

Micro-visualization techniques have been used to investigate the in vitro blood flow through straight glass capillaries. Although the glass microchannels present certain similarities to in vivo microcirculation, it is also clear that these kind of in vitro experiments differ from microvessels in several respects, such as: elasticity of microvessels, effect of the endothelial surface layer and microvascular netw...