CELLULOSE DERIVATIVES AS MEMBRANE MATERIA LS FOR HEMODIALYSIS STRUCTURE PROPERTIES RELATIONS

Modern strategies in developing new dialysis membranes aim to improve their blood compatibility This can be achieved by a chemical modificat ion of the membrane surface. Our investigations on systematically modi fied cellulosic membranes show that blood compatibility depends on the distribution of hydrophilic and hydrophobic domains on the membrane s urface. This distribution is determined by the type oi chemical substi tuent and its degree of substitution. As representative factors charac terizing hemocompatibility, we assessed the following parameters: comp lement activation (C5a), number of platelets in the surpernatant, and thrombin, measured as a complex with antithrombin III (TAT). Contact a ngle measurements have proven to be an appropriate physical tool for t he characterization of hemocompatibility of newly developed dialysis m embranes. The result of our investigations finally prove that the foll owing strategy is useful for the development of hemocompatible membran es: hydrophilic polymers should be modified with hydrophobic component s and hydrophobic polymers should be modified with hydrophilic compone nts, both in a controlled manner in order to achieve a hydrophilic/hyd rophobic balance (HLB) of surface domains.