Inner Surface Treatment of Haemodialysis Membranes

The zeta potential measurement assists in the improvement of the biocompatibility of haemodialysis membranes.

The extracorporeal haemopurification is the only chance to keep the patient alive over a period of time in the case of a chronicle or acute renal failure. Haemodialysis removes toxic substances from the blood and substitutes the functionality of the kidney.

For this process artificial polysulfone ultra-filtration (PSU) membranes arranged in a bundle of hollow fibers are widely applied. In order to improve the biocompatibility of the membrane and to avoid any complications upon contact with blood, the inner surface of the haemodialysis membranes needs modification.
The grafting of reactive carboxyl groups (COOH) onto the polysulfone surface is one route to prepare the interface for the immobilization of biologically active substances.

A comparison of the zeta potential of untreated and modified haemodialysis membranes reveals the efficiency of the membrane treatment.
The isoelectric point (IEP, pH where ζ = 0 mV) shifts from pH 5 for the untreated PSU membrane to pH 3.5 for the carboxylated membrane.

This shift of the IEP and the different course of zeta potential at high pH indicate the successful grafting of carboxyl groups onto the inner surface of the haemodialysis membrane.

Data provided by Fresenius Medical Care, Germany

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