POLYAMIDE-4,6 MEMBRANES FOR THE ENCAPSULATION OF LANGERHANS ISLETS - PREPARATION, PHYSICOCHEMICAL PROPERTIES AND BIOCOMPATIBILITY STUDIES

Porous polyamide 4,6 membranes developed as semi-permeable and biocomp atible membranes for the encapsulation of pancreatic islets were prepa red by precipitation in water. Different membrane morphologies were ob tained by varying the molecular weight of polyamide 4,6, the solvent e vaporation time and the composition of the casting solution. Each memb rane was submitted to differential scanning calorimetry and water flux measurements to study the total water content and the different kinds of water in correlation with its permeability performances. Their bio compatibility was first evaluated by a surface protein adsorption test . Of the various membranes, the one prepared by immersion in water aft er 5 minutes of solvent evaporation, of 15% KS200 polyamide 4,6 soluti on added with 1% of polyvinylpyrrolidone K30 seems to be the most prom ising. This membrane is characterized by a low adsorption of proteins, a high hydraulic coefficient and an asymmetric structure. Such a memb rane represents a good candidate to be an efficient immunological barr ier. It also exhibits good glucose and insulin diffusion properties. M oreover, rat islets cultivated on its surface were not affected by its presence and no important cell adhesion was noticed when implanted in mice. This membrane exhibits most of the properties suitable for the islet encapsulation with a view to developing a bioartificial pancreas .