Examination of particulate macroporous hydrogels in an extracorporeal rat haemoperfusion model

A series of macroporous hydrogels has been synthesized, selected from a ran ge of such materials in which the, presence of functional groups has been s hown to produce sorbent properties with respect to molecules having clinica l significance in the field of liver support. The use of freeze-thaw polyme rization, together with inverse suspension polymerization in hexane; or in brine, enables macroporous beads ranging in size from 150 to 2000 mu m, to be prepared from functional monomers exhibiting a range of chemical functio nalities and aqueous solubilities. In order to investigate the behaviour of these rigid porous hydrophilic substrates in haemoperfusion, a rat model w as used to explore various aspects of whole blood response; The materials w ere incorporated into an extracorporeal circuit linking the right cartoid a rtery and left jugular vein of male Sprague-Dawley mts. Erythrocyte, leucoc yte and platelet levels were monitored over a 240 min haemoperfusion period . The most significant observation is that, apart from the strongly acidic polyacrylic acid substrate, matrix chemistry has relatively little effect o n leucocyte or platelet response. The most important factors appear to be s urface area, pore size and surface rugosity, which do produce measurable, b ut not dramatic, differences. This is encouraging for future work, since th ese variables may be manipulated by polymerization conditions.