In-situ synchrotron quantitative analysis of competitive adsorption tendency of human serum proteins on polyether sulfone clinical hemodialysis membrane

Abstract

Comprehensive understanding of protein adsorption phenomenon on membrane surface during hemodialysis (HD) is one of the key moments for development of hemocompatible HD membrane. Though many mechanisms and kinetics of protein adsorption on some surface have been studied, we are still far away from complete understanding and control of this process, which results in a series of biochemical reactions that causes severe complications with health and even the death among HD patients. The aim of this study is to conduct quantitative analysis of competitive adsorption tendency of human serum protein on polyether sulfone (PES) clinical dialysis membrane. In situ synchrotron radiation micro-computed tomography (SR-µCT) imaging available at the Canadian Light Source (CLS) was conducted to assess human serum proteinbinding and undertake the corresponding quantitative analysis.The competitive adsorption of Human protein albumin (HSA), fibrinogen (FB) and transferrin (TRF) were tested from single and multiple protein solution. Furthermore, in-vitro human serum protein adsorption on clinical dialyzers was investigated using UV–Visible to confirm the competitive adsorption tendency. Results showed that when proteins were adsorbed from their mixture, FB content (among proteins) in the adsorbed layer increased from 3.6% mass (content in the initial solution) to 18% mass and 12%, in case of in situ quantitative and invitro analysis, respectively. The increase in FB content was accompanied by the decrease in the HSA content, while TRF remained on approximately on the same level for both cases. Overall, the percentage of HSA adsorption ratio onto the HD membrane has dropped approximately 10 times when HSA was adsorbed in competition with other proteins, compared to the adsorption from single HSA solution. The substitution of HSA with FB was especially noticeable when HSA adsorption from its single solution was compared with the case of the protein mixture. Moreover, SR-µCT has revealed that FB when adsorbed from a protein mixture solution is located predominately in the middle of the membrane, whereas the peak of the distribution is shifted to membrane bottom layers when adsorption from FB single solution takes place. Results showed that HSA FB and TRF adsorption behavior observations are similar on both in-situ small scale and clinical dialyzer of the PES membrane.