Polystyrene microspheres are widely used in biomedical applications due to their uniform size and surface properties. They serve as essential tools in diagnostic assays, including immunoassays and lateral flow tests, where they act as carriers for antibodies or antigens. Their consistent spherical shape and size distribution make them ideal for calibration of instruments such as microscopes and flow cytometers.

In drug delivery research, polystyrene microspheres are used as model particles to study release kinetics and cellular uptake mechanisms. They are also employed in cell sorting and separation techniques, where surface-functionalized microspheres bind to specific cell types for isolation.

Additionally, these microspheres are used in coatings and electronic materials to control surface texture, improve scratch resistance, or act as spacers in display technologies. Their optical properties make them useful in reflective paints, security inks, and visualization studies.