Back
Protein attachment to the surfaces and matrices of hemodialysis (HD) membranes is a highly undesirable occurrence since it triggers the activation of complement and results in severe health complications for HD patients. Nonetheless, there has been a noticeable absence of systematic investigation into the connection between membrane properties and their effectiveness in the dialysis procedure. This research endeavor seeks to offer a thorough comprehension of the competitive tendencies of three human serum proteins (namely, albumin (HSA), fibrinogen (FB), and transferrin (TRF)) to adhere to clinical dialysis membranes constructed from polyethersulfone (PES), polyacrylonitrile (PAN), and polyvinyl fluoride (PVDF) polymers.
To evaluate the structure of the membrane throughout its cross-section, in situ synchrotron radiation micro-computed tomography (SR-µCT) imaging at the Canadian Light Source (CLS) was used. In addition, an advanced synchrotron-based X-ray tomography method was employed to both qualitatively and quantitatively analyze protein adsorption. To understand how different protein types interacted and affected the overall protein adsorption, adsorption results from single-protein solutions with those from a mixture of proteins were compared. Gold nanoparticles conjugated with proteins produced the brightest spots on the images, allowing for the quantification of protein amounts adsorbed at each scanned layer. In the case of adsorption from a multiprotein solution, each protein was detected and analyzed based on the specific shape of the nanoparticles used for conjugation with each protein. Spherical particles were utilized for conjugation with HSA, rods (with a sphericity ratio of 0.85) were used for FB, and cylinders (with a sphericity ratio of 0.91) were used for TRF.
The initial protein mixture contained a low FB proportion (3.6%), but as adsorption occurred, FB content significantly increased (15% to 18.5%), varying by membrane type. HSA, predominant in the initial solution (91%), exhibited a notable reduction in adsorption from the protein mixture, as compared with adsorption from a single HAS solution. PES displayed the most significant decline in HSA adsorption, resulting in the lowest HSA content. PAN and PVDF membranes also exhibited reduced HSA adsorption. TRF adsorption remained consistent across all membranes. PES membrane had the highest FB content (18.5%), indicating a strong FB adsorption propensity.
FB competes effectively with HSA during adsorption, displacing a substantial portion. This suggests that FB may have a stronger interaction with the membrane or higher surface affinity. PES membranes showed the greatest inclination in FB adsorption. Fibrinogen adsorption during dialysis can activate blood, impacting platelet and neutrophil activation, contributing to the Vroman effect, and influencing secondary membrane formation on the dialyzer.