Related Experiment Video
Updated: Jun 8, 2026
10:27
Controlled Microfluidic Environment for Dynamic Investigation of Red Blood Cell Aggregation
Published on: June 4, 2015
Fluid particle diffusion through high-hematocrit blood flow within a capillary tube
Maryam Saadatmand1, Takuji Ishikawa, Noriaki Matsuki
1Department of Biomedical Engineering, Graduate School of Biomedical Engineering, Tohoku University, Sendai 980-8579, Japan. Saadatmand@che.sharif.edu
Journal of Biomechanics
|October 5, 2010
Summary
Red blood cell motion enhances tracer particle diffusion in capillary blood flow. Particle dispersion increases with flow rate and hematocrit, offering insights into microcirculation and microdevice mixing.
Area of Science:
- Biophysics
- Fluid Dynamics
- Biomedical Engineering
Background:
- Understanding fluid particle diffusion in capillary blood flow is crucial for microcirculation mass transport.
- Technical challenges in mixing within biomedical microdevices necessitate research into particle dispersion.
Purpose of the Study:
- To investigate tracer particle diffusion in blood with varying hematocrit levels flowing through a capillary tube.
- To quantify the impact of red blood cell motion on particle dispersion.
Main Methods:
- Utilized a confocal micro-particle tracking velocimetry (PTV) system to track hundreds of particles.
- Measured the radial dispersion coefficient in blood with hematocrit up to 20%.
Main Results:
- Observed significant enhancement of particle diffusion due to micron-scale flow fields generated by red blood cells.
- Particle dispersion showed a near-linear increase with flow rate and hematocrit (up to 20%).
- Tracer particle dispersion was approximately 0.7 times that of red blood cells.
Conclusions:
- Red blood cell dynamics play a key role in enhancing particle dispersion in microfluidic blood flow.
- Findings provide valuable insights for mass transport in microcirculation and the design of biomedical microdevices.
Related Concept Videos
01:28Capillary Exchange
The cardiovascular system's chief role is to disseminate gases, nutrients, waste, and other substances to the body's cells. Small molecules like gases, lipids, and lipid-soluble substances directly diffuse through capillary wall endothelial cell membranes. Glucose, amino acids, and ions, including sodium, potassium, calcium, and chloride, use transporters for facilitated diffusion via membrane-specific channels. Glucose, ions, and bigger molecules may also pass through intercellular clefts.
01:20Capillary Beds
Capillary beds are networks of tiny blood vessels that play a crucial role in the circulatory system. These beds are where the exchange of gases, nutrients, and waste products occurs between the blood and surrounding tissues. Each capillary bed consists of numerous capillaries, which are the smallest blood vessels in the body, typically only one cell-thick. This thinness allows for the efficient diffusion of substances.
Capillaries connect arterioles, small branches of arteries, to venules,...
Capillaries connect arterioles, small branches of arteries, to venules,...
01:19Capillarity in Fluid
Capillarity describes the movement of liquid in small spaces without external forces acting on it. The capillarity is driven by surface tension and adhesive interactions between the liquid and surrounding solid surfaces. This effect is often seen in narrow tubes, porous materials, and fine particles.
Surface tension is crucial to capillarity. It results from cohesive forces between liquid molecules at the liquid-air boundary, forming a skin that resists external forces. When the capillary tube...
Surface tension is crucial to capillarity. It results from cohesive forces between liquid molecules at the liquid-air boundary, forming a skin that resists external forces. When the capillary tube...
01:23Steady, Laminar Flow in Circular Tubes
Hagen-Poiseuille flow describes a viscous fluid's steady, incompressible flow through a cylindrical tube with a constant radius R. This flow profile is often applied to understand fluid transport in narrow channels, such as capillaries. It serves as a foundational example of laminar flow. In this model, cylindrical coordinates (r,θ,z) are used to describe the radial (r), angular (θ), and axial (z) dimensions within the tube. For Hagen-Poiseuille flow, the velocity profile is purely axial,...
00:57Physiological Pharmacokinetic Models: Blood Flow-Limited Versus Diffusion-Limited Models
Physiological pharmacokinetic models, often called flow-limited or perfusion models, typically assume a swift drug distribution between tissue and venous blood, creating a rapid drug equilibrium. This premise is based on the idea that drug diffusion is extremely fast, and the cell membrane presents no barrier to drug permeation. In this scenario, where no drug binding occurs, the drug concentration in the tissue equals that of the venous blood leaving the tissue. This greatly simplifies the...
01:29Blood Flow
Blood is pumped by the heart into the aorta, the largest artery in the body, and then into increasingly smaller arteries, arterioles, and capillaries. The velocity of blood flow decreases with increased cross-sectional blood vessel area. As blood returns to the heart through venules and veins, its velocity increases. The movement of blood is encouraged by smooth muscle in the vessel walls, the movement of skeletal muscle surrounding the vessels, and one-way valves that prevent backflow.