Selective sorbent removal system using polycation activated substrates

Abstract

A polycationic system for the removal of polyanions from a fluid medium is formed by, first, activating a biocompatible hydroxylated support with an organic sulfonyl chloride, such as p-toluene-sulfonyl chloride, in the presence of a dialkylamino pyridine activation catalyst, such as 4-dimethylamino-pyridine (DMAP). The activated support is then reacted with a polymer having a polyamide backbone with pendent alkyl amine groups, such as poly-L-lysine (PLL), to form C--N bonds between an activated carbon from the hydroxylated polymer and an amine group from the polymeric polyamide. Finally, any unreacted activated sites on the hydroxylated polymer are capped or removed with an effective amount of capping agent such as a mercapto (--SH), hydroxy (--OH) or amino (--NH.sub.2) containing compound which reacts with the unreacted activated sites. The pendent alkyl amines on the polyamide backbone exist, at the appropriate pH, as polycations. The polyanion, such as heparin, is removed from fluids, such as blood plasma and whole blood, by bringing these fluids in contact with the polycationic system. The polyanion is bound to the polycation system by ionic attraction. The polyanion can then be released from the polycation system by treatment with a basic solution, thereby allowing the system to be reused.