Use of macromolecules in microparticles

POLYMERS of acrylamide, dextran, Agarose, and their derivatives have been used widely as matrices for covalent immobilisation of enzymes, for example, for biospecific affinity chromatography 1 . Macromolecules can also be trapped in acrylic polymers, when added to the monomer solution before polymerisation 2–4 . Spherical polymeric particles are produced by homogenising the monomer solution with a suitable detergent in an organic solvent or mixture, in such a way as to produce a water–oil emulsion before polymerisation. The size of the polymeric particles will be directly proportional to the size of the droplets of the monomeric solution in the organic phase, giving a narrow size-distribution of the particles. The mean diameter can be varied greatly by changing the homogenising conditions. Hitherto, the aim has been to prepare particles with a mean diameter of 100–250 µ m, to ensure a high flow rate when they are packed in columns. We have now found, however, that macromolecules trapped in the particles, retain their biological properties, and that therefore, microparticles with mean diameter