Covalent Bonding of Heparin on the Crystallized Poly(lactic acid) (PLA) Membrane to Improve Hemocompability via Surface Cross Linking and Glycidyl Ether Reaction

The hemocompatibility of the dialysis membrane has been considered the key factor influencing the dialysis performance for curing the kidney malfunction. In this work, the commonly used anticoagulant heparin in the clinic was directly bonded to the poly(lactic acid) (PLA) membrane to improve the hemocompatibility via the glycidyl ether reaction. A novel precopolymer P(VP-VTES-GMA) was first prepared via free radical polymerization. The surface cross-linking of the precopolymer containing GMA segments enabled the membrane to anchor heparin through the glycidyl ether reaction. The chemical structure of the precopolymer was confirmed by NMR. The surface chemistry was analyzed by XPS, toluidine blue staining, and solubility tests. The crystallization behavior, heat resistance, morphology, hydrophilicity, pore size, and pure water flux were investigated. The hemocompatibility was comprehensively investigated via APTT, PRT, PT, FIB, and platelet adhesion tests. The simulated dialysis performances relating to urea, creatinine, lysozyme, and BSA clearance were measured. All results demonstrated that the covalent bonding of heparin provided the PLA membrane with excellent hemcompatibility, hydrophilicity, heat resistance, and dialysis performance as well.