Replication of fouling in vitro in hollow fiber dialyzers by albumin immobilization.

For designing and evaluating the dialyzer and investigating the optimal therapeutic conditions, in vitro studies bring us many useful findings. In hemodialysis, however, the membrane fouling due to protein molecules reduces solute removal performance. Therefore, we investigated a method for replicating the fouling in dialyzers in aqueous experiments. After the albumin solution was circulated in the test circuit with a dialyzer, a glutaraldehyde solution was pumped into the dialyzer to immobilize albumin on the hollow fiber membrane. Under various immobilization conditions, the permeability of creatinine and vitamin B12 was evaluated by dialysis experiments. The creatinine clearance after immobilization of albumin was decreased, suggesting pore plugging by our fouling replication method. The glutaraldehyde crosslinked albumin molecules that adhered them to the membrane firmly. Moreover, the degree of fouling may be controlled by changing the concentration of albumin solution and the volume of glutaraldehyde solution used for immobilization. Our fouling replication method was applied to three types of polyester polymer alloy (PEPA) dialyzers and one polysulfone (PSf) dialyzer. This method enables to evaluate the permeability of various dialyzers with fouling in vitro that will be of great help in collecting data for designing dialyzers.