STUDIES IN POLYMER SURFACE MODIFICATION AND GRAFTING FOR BIOMEDICAL USES .2. APPLICATION TO ARTERIAL BLOOD FILTERS AND OXYGENATORS

The technique for polymer surface modification described in earlier pa pers has been applied to two components of an extracorporeal blood cir culatory system used in open-heart surgery, with the object of improvi ng their haemocompatibility. The devices were the arterial blood filte r composed of nylon membranes and the blood oxygenator consisting of p olypropylene microporous hollow fibres. Polyacrylamide and, in some ca ses, a mixture of polyacrylamide and poly(3-aminopropyl methacrylamide ) have been covalently attached to the blood-contacting surfaces. The basic groups of the latter polymers provided a means of coupling hepar in to the surface. The extent of heparin coupling was determined by ra dioactivity measurements with the aid of S-35-labelled heparin. The fo llowing determinations were made to assess haemocompatibilities: blood plasma clotting times (PTT); platelet adhesion to the nylon filters; concentrations of lymphocytes and neutrophils in whole blood after exp osure to the surfaces. It is concluded that the overall process, which has the merits of cheapness and simplicity in application, has a bene ficial effect on haemocompatibility. Copyright (C) 1996 Elsevier Scien ce Ltd.