Monodisperse carboxy silica microspheres are widely used in chromatography for efficient separation and purification of biomolecules due to their uniform size and surface functionalization. They serve as excellent carriers in drug delivery systems, enabling targeted release and enhanced stability of therapeutic agents. In diagnostics, these microspheres are employed as solid supports for immunoassays, improving sensitivity and specificity in detecting biomarkers. They are also utilized in the fabrication of advanced materials, such as photonic crystals, where their precise size and carboxyl groups facilitate self-assembly and surface modification. Additionally, they play a role in environmental applications, including water purification and pollutant adsorption, owing to their high surface area and functional properties.