Carboxylate-modified polystyrene latex beads are widely used in biomedical research and diagnostics due to their uniform size and surface functionalization. They serve as excellent carriers for the covalent attachment of biomolecules such as antibodies, proteins, and nucleic acids, making them valuable in immunoassays, flow cytometry, and cell sorting applications. These beads are also utilized in the development of biosensors, where their carboxyl groups enable precise immobilization of target molecules. Additionally, they are employed in drug delivery systems to enhance the stability and targeting efficiency of therapeutic agents. In material science, they act as model colloids for studying particle interactions and self-assembly processes. Their versatility and ease of modification make them a critical tool in both research and industrial applications.