Polymeric microspheres as diagnostic tools for cell surface marker tracing.

The adequate expression of cell-surface receptors and antigens is an important requirement for the functional ability of living cells. A lot of different methods for cell surface marker tracing have been described; however, most of these techniques have disadvantages limiting their wide-scale utilization in routine laboratory and clinical practice. The most recent technique for these purposes, approaching near the ideal one, is based on the use of synthetic microspheric particles made of polymers which are formed mainly by emulsion or radiation polymerization of a variety of monomers. The resulting spherical particles bear hydroxyl, carboxyl, amino, or other functional groups capable of covalent binding of proteins, dyes, or chemotherapeutic agents. Fluorescent, radioactive or haptenic labels may be introduced already during the polymerization, too. There are three main fields of application of such specific labeled microspheres in cell biology: (1) detection of cell surface markers; (2) studies of phagocytosis mediated via cell surface markers; and (3) cell separation according to cell surface markers. In this review general principles of preparation and applications of polymeric microspheres in cell biology are summarized.