Magnetic ferrofluids for preparation of magnetic polymers and their application in affinity chromatography

Abstract

THE use of magnetic polymers as supports for biological molecules has created much interest^1–5. The inherent advantages of such preparations are, in particular, the ease of recovery of these polymers by applying a magnetic field. Thus, when used as supports for immobilised enzymes, their easy retrieval from liquors containing colloids or undissolved solids should be of great practical value^1–3. Magnetic polymers have recently been tested as an alternative to conventional radioimmunoassay technique, obviating the need for vertical rotation and for the time-consuming, multiple centrifugations required with conventional solid phase procedures^4–5. In the established techniques for producing magnetic polymer particles, the attachment of the biomolecules had to follow the preparation of the specific magnetic material; furthermore most of these preparations have been non-porous, exhibiting rather poor capacity. We describe here a novel and general procedure using magnetic fluids which allows ‘post-magnetisation’ of polymers already substituted with biological molecules. The properties of such preparations have been tested primarily as affinity chromatography gels. These preparations showed unaltered biospecificity when applied in general ligand-affinity chromatography studies. The simplified separation possible due to the magnetic properties of the gels eliminates the usual centrifugation and column chromatography steps. The procedure of ‘post-magnetisation’ seems to be suitable for different polymer particles, both unsubstituted gels and those carrying immobilised ligands as affinity adsorbents or enzymes.