Computational modeling reveals flow-dependent apparent viscosity in narrow capillaries, indicating red blood cell membrane mechanics dictate microvascular resistance.
Key Points
To theoretically model the flow of axisymmetric red blood cells through narrow capillaries and examine the influence of membrane elasticity on apparent blood viscosity across varying velocities.
Modeled cylindrical capillaries with internal diameters up to 8 μm assuming axisymmetric red blood cell geometries.
Applied lubrication theory to characterize the motion of suspending fluid within cell-vessel gaps.
Incorporated elastic membrane mechanics, including shear, bending, and isotropic tension stresses.
At moderate or high cell velocities (approximately ≥1 mm/s), membrane stress approximates isotropic tension peaking at the cell nose, causing cell shape and apparent viscosity to remain independent of flow velocity.
At lower flow velocities, membrane shear and bending stresses become dominant, resulting in an increase in apparent blood viscosity as flow rate decreases.