FluoSpheres Sulfate-Modified Microspheres are loaded with our proprietary fluorescent dyes, making them the brightest microspheres available. Because the fluorescent dye molecules are contained inside each polystyrene microsphere instead of only on the surface, the dye molecules are shielded from many of the environmental effects that cause quenching or photobleaching of exposed fluorophores. The stability, uniformity, and reproducibility of FluoSpheres microspheres, as well as their extensive color selection, make them the preferred tools for research and diagnostic assays that use fluorescence.

FluoSpheres Sulfate-Modified Microspheres are relatively hydrophobic particles that will passively and nearly irreversibly adsorb almost any protein, including albumin, IgG, avidin, and streptavidin.

Key applications of FluoSpheres Sulfate-Modified Microspheres
• Instrument calibration (flow cytometry, microscopy, HTS, HCS)
• Flow testing (microfluidics, blood flow, water flow, and air flow)
• Cell biology tracers (cell differentiation and cell tracing)
• Immunoassays (agglutination tests, ELISA, particle capture, and contrast reagents)

FluoSpheres sulfate-modified microsphere specifications for F8845, F8848, F8852, F8853, and F8859:
• Label (excitation/emission): yellow-green (505/515)
• Nominal bead diameters: 0.02, 0.2, 1.0, 2.0, and 4.0 μm
• Coupling surface: sulfate
• Solids: 2%

FluoSpheres sulfate-modified microsphere specifications for F8851 and F8858:
• Red (580/605)
• Nominal bead diameters: 1.0, 4.0 μm
• Coupling surface: sulfate
• Solids: 2%

FluoSpheres fluorescent microspheres are potentially more sensitive than colorimetric methods in most, if not all, major microsphere-based diagnostic test systems presently in use, including microsphere-agglutination tests, filter separation tests, particle-capture ELISA methods, and two-particle sandwich techniques.

FluoSphere Sulfate-Modified Microspheres (also called latex beads or latex particles) are manufactured using high-quality, ultra-clean polystyrene and are loaded with a variety of our proprietary dyes to create intensely fluorescent beads that typically show little or no photobleaching, even when excited with the intense illumination required for fluorescence microscopy. Every possible precaution is taken throughout the manufacturing process to ensure that the microparticles are kept free of contaminating agents. The final product is sold as a suspension in ultrapure water, in most cases containing 2 mM azide or 0.02% thimerosal as a preservative.

Other surface modifications are available to facilitate the coupling of various molecules and proteins to the surface of the bead, including amine- and carboxylate-modified FluoSphere microspheres.

Choices for unstained microspheres
We also offer hundreds of choices for ultra-clean surfactant-free microspheres for research and commercial applications.

Custom microspheres
We prepare custom microspheres upon request. For example, FluoSpheres Sulfate-Modified microsphere beads can be prepared with intensities that are lower than those of our regular selection, a desirable feature in some multicolor applications. Our custom conjugation service is efficient and confidential, and we guarantee the quality of our work. We are ISO 13485:2000 certified.