Escherichia coli (K-12 strain) BioParticles™, fluorescein conjugate

The Molecular Probes™ BioParticles™ product line consists of a series of fluorescently labeled, heat- or chemically killed bacteria and yeast in a variety of sizes, shapes, and natural antigenicities. These fluorescent BioParticles™ products have been employed to study phagocytosis by fluorescence microscopy, quantitative spectrofluorometry, and flow cytometry.

We offer E. coli (K-12 strain), S. aureus (Wood strain, without protein A) and zymosan (S. cerevisiae) BioParticles™ conjugates covalently labeled with a variety of different fluorophores (special care has been taken to remove free dye after conjugation). Unlike the fluorescence of fluorescein-labeled BioParticles™ conjugates, which is partially quenched in acidic environments, the fluorescence of the Alexa Fluor™, BODIPY™ FL, tetramethylrhodamine and Texas Red™ dye conjugates is uniformly intense over the pH range from 3 to 10.

BioParticles Specifications:
• Label (Ex/Em): Fluorescein (∼494/518 nm)
• Particle: E. coli (K-12 strain)
• Opsonizing reagent available

Using BioParticles Products
BioParticles™ conjugates are provided as lyophilized powders. There are approximately 3 x 108 E. coli or S. aureus particles per mg solid and approximately 2 x 107 zymosan particles per mg solid. BioParticles™ conjugates can be reconstituted in the buffer of your choice for use in phagocytosis assays. The fluorescence of BioParticles™ conjugates that are bound to the surface of the cell (but not internalized) can be quenched by ethidium bromide, trypan blue, or other quenchers. In addition to cellular applications, fluorescent BioParticles™ conjugates may be effective as flow cytometry calibration references when sorting bacteria and yeast mutants. These small particles may also be useful references for light scattering studies because their sizes and shapes differ in characteristic ways.

Find More BioParticles™ Products
We offer a large range of dye-labeled and unlabeled E. coli (K-12 strain), S. aureus (Wood strain, without protein A), and zymosan (S. cerevisiae) BioParticles™ products. Find out about these products and their applications by reviewing Probes for Following Receptor Binding and Phagocytosis—Section 16.1 in the Molecular Probes™ Handbook.

For pH-sensitive endocytosis assays, see our pHrodo™ BioParticles™ conjugates.

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