Study On Surface Compatibility Modification And Dialysis Properties Of Polylactic Acid Microporous Membrane

Polylactic acid(PLA)possesses good film-forming property,controllable degradation,easy structure regulation and high value-added as a bio-based material.However,the anti-fouling properties and biocompatibility of PLA microporous membrane limited its application in hemodialysis to some extents.In this paper,the PLA microporous membranes were prepared by the methods of non-solvent induced phase separation,and modified for improved hydrophilicity via micro-swelling and interfacial crosslinking strategy.And then anticoagulant groups(such as heparin,hirudin and heparin-mimicking)were immobilized onto the membrane surface to improve the fouling resistance,hemocompatibility and dialysis performance of PLA microporous membrane.The main research contents were listed as follows: covalent bonding of heparin on the PLA membrane to improve hemocompability;novel hirudin facilitated anti-clotting PLA membrane via hydrogen bonding interaction;heparin-mimicking modified PLA membrane for improved hemocompatibility.The physical and chemical structure,hydrophilicity,blood compatibility and dialysis performance of the membrane were studied in details.The conclusions can be made as follows:(1)Heparin was successfully immobilized onto the surface of PLA membrane by amidation reaction and adsorption,which greatly improved the hemocompatibility of PLA membrane.Firstly,Hep-APTES was synthesized by amidation reaction.Then the Hep-APTES was facilitated to the surface of PLA membrane through condensation and multilayer adsorption.All the experimental results showed that the heparin immobilized PLA membrane had good hemocompatibility.(2)Natural hirudin was immobilized on PLA membrane surface through hydrogen bonding interaction to prepare anti-coagulation PLA membrane.Four items of blood coagulation(APTT,PT,TT and FIB)test results showed that hirudin facilitated membrane had good hemocompatibility.Dialysis experiments showed that the new preparation of hirudin facilitated PLA membrane had good urea,creatinine and lysozyme clearance rate and higher BSA retention.(3)Heparin-mimicking copolymer P(SSNa-VTES-AAH)was synthesized and then immobilized on the membrane surface by micro-swelling and interfacial crosslinking,so as to improve the hemocompatibility of PLA membrane.The hemocompatibility of heparin-mimicking modified PLA membrane was obviously improved,and the amount of platelet adsorption was reduced.