MONOSIZE MICROBEADS BASED ON POLYSTYRENE AND THEIR MODIFIED FORMS FORSOME SELECTED MEDICAL AND BIOLOGICAL APPLICATIONS

Polymeric particles are produced by different polymerization technique s. Phase inversion (dispersion) polymerization is one of the recent te chniques to obtain monosize polymeric microbeads in the size range of 1-50 mu m. The size and monodispersity of these microbeads can be adju sted by using several solvent systems (e.g., alcohol-water mixtures) w ith different polarities and by changing the type and amount of monome r, initiator and stabilizer. Surfaces of these microbeads can be furth er modified by different techniques including coating with different c opolymers. Monosize polymeric microbeads are widely used in medical an d biological applications as carriers, such as in immunoassays and cel l separation, in site-specific drug delivery systems, in nuclear medic ine for diagnostic imaging, in studying the phagocytic process, in aff inity separation of biological entities, etc. Here, some important asp ects of the production of monosize microbeads based on polystyrene and their modified forms are briefly discussed, and some selected medical and biological applications are summarized.