Abstract:

A novel composite affinity adsorption material bearing polyvinylimidazole(PVI) as the ligand for selective removal of endotoxin(ET) was prepared by graft polymerization of vinylimidazole onto silica gel particles in DMF(N,N-dimethyl-formamide). The characteristic bands of imidazole ring at 1500 cm^-1 and 665 cm^-1 were detected via FTIR and the grafting degree(GD) of PVI was measured with TGA according to the weight loss of the sample. The ET adsorption capacity of the sorbents shows dependence on GD of PVI on the sorbent, and the maximum ET adsorption capacity was attained with GD of 2.5%. The effects of ionic strength and pH values of the testing solution on the sorbent performance were also studied. At pH=7 and ionic strength lower than 1 mol/L the sorbent had the best adsorption ability toward ET even in presence of BSA. The sorbent shows a good blood compatibility. The adsorption kinetics and the isotherm of the sorbent were well accorded with the second order equation and Freundlich equation, respectively. The results reveal the applicability of PVI or other compounds with imidazole group to serve for good ligand in ET removal.

Key words: Endotoxin, Affinity adsorption, Vinylimidazole, Graft copolymerization