http://www.cd-bioparticles.com/p/Carboxyl-Magnetic-Particles_20_193_211_341.htmlAbsolute Mag Carboxyl Magnetic Particles, Fluorescent Yellow, 4.0-4.9 μm (# WHM-S155) are prepared by either staining the polystyrene core of the particles with a solution of appropriate fluorophore or by polymerizing a fluorophore in styrene in the presence of polystyrene core particles. They can be covalently coupled to proteins or ligands and used as fluorescent tracers for cell surface markers in fluorescence microscopy and flow cytometry. Proteins/Ligands Immobilization, Fluorescence Imaging