In situ synchrotron quantitative analysis of competitive adsorption tendency of human serum protein to different clinical hemodialysis membranes and assessment of potential impacts

Protein adsorption on hemodialysis (HD) membrane matrices and surfaces is a highly undesirable process, as it triggers complement activation and leads to severe health complications for HD patients. However, there is a lack of systematic research investigating the correlation between membrane characteristics and their performance in the dialysis process. This study aims to provide a comprehensive understanding of the competitive adsorption tendencies of three human serum proteins (albumin (HSA), fibrinogen (FB), and transferrin (TRF)) on clinical dialysis membranes composed of polyethersulfone (PES), polyacrylonitrile (PAN), and polyvinyl fluoride (PVDF) polymers. To assess membrane morphology across the membrane cross-section, in situ synchrotron radiation micro-computed tomography (SR-µCT) imaging was conducted at the Canadian Light Source (CLS). Protein adsorption was analyzed qualitatively and quantitatively using an innovative synchrotron-based X-ray tomography technique. To determine the mutual influence of protein species on overall protein adsorption, adsorption from single-protein solutions was compared to adsorption from a protein mixture. Regarding single-protein adsorption, the PVDF membrane exhibited 40% less adsorption of HSA compared to the PES membrane. Conversely, FB adsorption was approximately 25% higher on the PVDF membrane compared to the PES membrane. The PAN membrane showed similar levels of HSA adsorption as the PES membrane and similar levels of FB adsorption as the PVDF membrane. In the case of adsorption from the protein mixture, a suppression of HSA adsorption and replacement of HSA with FB were observed. Consequently, the initial solution with a HSA content of 92% resulted in an adsorbed layer containing approximately 75–80% HSA across all the studied membranes. TRF adsorption remained unaffected by the presence of other proteins, consistent across all three membranes. Notably, the PES membrane exhibited the most significant change in the adsorbed protein composition between single-protein and multi-protein adsorption. In addition, this study comprehensively assesses the impact of fibrinogen adsorption on dialysis, including its consequences, blood activation, and implications for quality of life.