The transport of nanoparticles in blood vessels: The effect of vessel permeability and blood rheology

The longitudinal transport of nanoparticles in blood vessels has been analyzed with blood described as a Casson fluid. Starting from the celebrated Taylor and Aris theory, an explicit expression has been derived for the effective longitudinal diffusion (D-eff) depending non-linearly on the rheological parameter xi(c), the ratio between the plug and the vessel radii; and on the permeability parameters Pi and Omega; related to the hydraulic conductivity and pressure drop across the vessel wall, respectively. An increase of xi(c) or Pi has the effect of reducing D-eff, and thus both the rheology of blood and the permeability of the vessels may constitute a physiological barrier to the intravascular delivery of nanoparticles.