Structural Delineation of the Exeltra Plus 210 Hemodialyzer’s Capillary Pores as Targets to Ameliorate Its Filtration

Abstract

Aim: To examine potentials to improve solute flux of selected uremic toxins across EXELTRA Plus 210 membrane. Methodology: Scanning electron microscopy was used to measure the inner and outer fenestrations of the membrane. We selected endothelin, β2-microglobulin, and complement factor D as uremic toxins for this study. The effective diffusivities of these molecules, Deff, were estimated using the equation Deff = Kdiff Do, under different conditions of fenestration densities and capillary diameters, where the hindrance factor, Kdiff, was calculated using the equation Kdiff = (ε / 2 - ε)2. Results: We estimated the innermost and outermost fenestrations mean pore densities to be 2.71% and 12.06%, respectively. Provided that the fenestrations’ density of the inner walls remained constant, doubling of the capillaries’ diameter and reducing their numbers by half, reduced Kdiff. Applying an electric potential across the outer surface of the capillaries increases the flux of the uremic toxins. Conclusion: The potential to improve the diffusive transport of uremic toxins through the capillaries’ walls could be enhanced by doubling the inner diameters of the capillaries, increasing the fenestrations density on the inner walls, and applying an electric potential.