Large agarose beads for extracorporeal detoxification systems.

A method is reported by which agarose beads of diameter 1000 to 10000 microns can be prepared from Sepharose (R) 4B (native bead diameter 40 to 190 microns). Haemoperfusion experiments indicate that the enlarged beads are relatively haemocompatible; platelet loss is considerably less than that reported for many other bio-materials employed in haemoperfusion, and haemolysis is slight even after perfusion for several hours at flow-rates in excess of 25 ml/min. The beads can be activated by cyanogen bromide for the immobilisation of proteins. The sites for protein fixation are not restricted to the outside surface of the beads; small water soluble molecules, and serum proteins diffuse quite rapidly through the enlarged beads. A possible medical application of the large beads is in extracorporeal detoxification by chromatographic extraction or enzymatic modification, particularly of lipophilic toxins, using the enlarged beads as a carrier-matrix. The results described in this publication prove the viability of this concept. Such methods should be especially useful as artificial supports in fulminant hepatic failure.