Microspheres (also called latex beads or latex particles) are spherical particles in the colloidal size range that are formed from an amorphous polymer such as polystyrene. Our Molecular Probes® luminescent FluoSpheres® beads are manufactured using high-quality, ultraclean polystyrene and are coupled with platinum or europium to produce a tracer with a long lifetime (platinum and europium microspheres exhibit decay times of >600 microseconds compared to <50 nanoseconds for conventional fluorophores). Platinum and europium luminescent FluoSpheres® beads are useful for detecting a low-level protein or DNA target in a tissue sample or on a membrane in time-gated fluorescence detection schemes.

In addition, the carboxylate surface modification is available to facilitate the coupling of various molecules and proteins to the surface of the bead.

FluoSpheres® Microsphere Specifications:
• Label (Ex/Em): Luminescent europium (365/610)
• Nominal bead diameter: 0.04 µm
• Coupling surface: Carboxylate
• Surface modification: Europium
• Solids: 0.5%

Characteristics of the Carboxylate Coupling Surface
Carboxylate-modified FluoSpheres® beads have a high density of pendent carboxylic acids on their surface, making them suitable for covalent coupling of proteins and other amine-containing biomolecules using water-soluble carbodiimide reagents such as EDAC.

Choices for FluoSpheres® Fluorescent Microspheres
Among our complete offering of fluorescent microspheres products, you’ll find beads with these variations:
• Ten fluorescent colors
• Ten nominal bead diameters: 0.02 µm, 0.04 µm, 0.1 µm, 0.2 µm, 0.5 µm, 1.0 µm, 2.0 µm, 4.0 µm, 10.0 µm, and 15.0 µm
• Four surface modifications for protein coupling: carboxylate, sulfate, aldehyde-sulfate, amine
• Microspheres that are additionally precoupled with streptavidin, NeutrAvidin, biotin, europium, and platinum

Choices for Unstained Microspheres
We also offer hundreds of choices for UltraClean™ surfactant-free microspheres for research and commercial applications.

We’ll Make a Custom Microsphere Product for You
We will prepare custom orders upon request. For example, FluoSpheres® 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 stand by the quality of our work. We are ISO 9001:2000 certified.

For Research Use Only. Not intended for animal or human therapeutic or diagnostic use.