PROSTAGLANDIN-E1-IMMOBILIZED POLY(VINYL ALCOHOL)-BLENDED CHITOSAN MEMBRANES - BLOOD COMPATIBILITY AND PERMEABILITY PROPERTIES

A series of membranes are prepared by air drying thin films, which were composed of poly(vinyl alcohol) blended with chitosan [a(1 --> 4)2-amino-2-deoxy-beta-D-glucan] (PVA-Chit) in different ratios. The PVA-blended chitosan membranes showed improved strength properties and permeability functions for low-molecular-weight compounds. Nonthrombogenic PVA-Chit (4 : 6) membranes were derived by immobilizing bioactive molecules like PGE1 on heparin-modified membranes, via free radical mechanisms, by N2 plasma. This novel membrane demonstrated good permeability properties for small molecules and showed a dramatic reduction in platelet attachement. The prostaglandin E1-immobilized substrate also indicated an increase in albumin surface attachment and a reduction in fibrinogen binding. This may be one of the parameters for a reduced platelet-surface attachment, which may also improve the blood compatibility of the substrate. It is also postulated that the total water content of membranes need not be the prime factor governing the permeability of solutes through water-swollen membranes. However, many other parameters govern the solute permeability, like the amount of solutes dissolved in bound water and the status of water in the polymer matrix.