A Multichamber Pulsating-Flow Device With Optimized Spatial Shear Stress and Pressure for Endothelial Cell Testing.

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Cell Biology

Background:

• Endothelial cells are crucial in vascular health.
• Understanding their response to mechanical forces is vital for disease research.
• Existing devices may not accurately replicate complex physiological conditions.

Purpose of the Study:

• To design and analyze a new device simulating simultaneous cyclic shear stress and pressure fluctuations.
• To ensure uniform mechanical stimuli for endothelial cell testing.
• To optimize device geometry for accurate cellular response studies.

Main Methods:

• Development of a pulsatile-flow chamber system with four series-connected chambers.
• Mathematical modeling of unsteady lubrication flow to determine shear stress distribution.
• Numerical integration of Laplace's equation for stream function analysis.
• Optimization of chamber planform, focusing on a hexagonal design.
• Experimental validation using particle tracking velocimetry (PTV).

Main Results:

• The device achieves identical shear stress across all chambers.
• Pressure amplitude decreases sequentially, with minimal intrachamber variations.
• The hexagonal planform optimizes spatial uniformity of shear stress.
• PTV experiments validated theoretical predictions of flow dynamics.
• The Womersley number is typically of order-unity, relevant for physiological conditions.

Conclusions:

• The developed device effectively simulates combined shear stress and pressure fluctuations.
• The optimized hexagonal chamber design ensures reliable and uniform mechanical stimuli.
• This tool advances the study of endothelial cell mechanobiology.
• Accurate simulation of physiological forces aids in understanding vascular diseases.