Carboxylate-modified polystyrene latex beads are widely used in biomedical research and diagnostics. Their surface modification with carboxyl groups allows for easy conjugation with biomolecules such as antibodies, proteins, or nucleic acids, making them ideal for applications in immunoassays, flow cytometry, and cell sorting. These beads serve as reliable calibration standards for particle sizing instruments due to their uniform size and stability. In drug delivery systems, they are utilized as carriers for targeted therapy, enhancing the precision of drug release. Additionally, they are employed in biosensing platforms to detect specific analytes with high sensitivity. Their biocompatibility and functional versatility make them valuable in both research and clinical settings.