Invitrogen™ pHrodo™ Phagocytosis Kit

pHrodo™ Red E. coli BioParticles™ Phagocytosis Kit for Flow Cytometry


  • Specifically detect phagocytosis and endocytosis with pH-sensitive fluorogenic dye - discriminate endcytosed from adherent and extracellular particles
  • Reduced signal variability and improved timing in sensitive experiments - no need for wash steps or quencher dye
  • Bright red fluorescence - conveniently multiplex with green dyes such as GFP, Fluo-4, or calcein

View a selection guide for all pHrodo Indicators used in imaging, flow cytometry and microplate assays.

The pHrodo™ Red dye gives faster and more accurate results than any other phagocytosis assay

The new Molecular Probes™ proprietary pH-sensitive rhodamine-based pHrodo™ Red dye is non-fluorescent at neutral pH, but turns bright red upon acidification. Because it is both fluorogenic and pH-sensitive, the pHrodo™ Red dye can be used as a specific sensor of phagocytic events; acidification of the phagosome following phagocytosis is marked by red fluorescence. It is therefore an ideal tool with which to study phagocytosis and its regulation by drugs and/or environmental factors.

Rapid and reproducible

Wash steps and quencher dyes are not needed since the pHrodo™ Red dye is non-fluorescent outside the cell, making the staining protocol simple and fast. The elimination of wash steps and quencher dyes also improves assay reproducibility, particularly in plate reader-based assays.

Flexible applications

Use ready-made pHrodo™ Red BioParticles™ conjugates for convenient analysis of phagocytosis of Gram-positive or Gram-negative bacteria, or the amine-reactive pHrodo™ Red SE form for labeling microorganisms or proteins of your choice.

Compatible with multiple platforms
pHrodo™ Red dye conjugates can be used in plate readers, fluorescence microscopy imaging, and flow cytometry applications. The pHrodo™ Red Phagocytosis Particle Labeling Kit and the pHrodo™ Red E. coli BioParticles™ Phagocytosis Kit for flow cytometry were designed for rapid and convenient measurements of phagocytic activity in whole blood samples by flow cytometry. The kits include all the reagents required for assessing particle ingestion and red blood cell lysis. The Labeling Kit also contains the reagents required for labeling microorganisms with the pHrodo™ Red dye. Sufficient reagents are provided in both kits for approximately 100 assays.

The optimal absorption and fluorescence emission maxima of the pHrodo™ Red BioParticles™ conjugate is approximately 560 nm and 585 nm, respectively. However, the fluorophore is readily excited with the 488 nm argon-ion laser installed on most flow cytometers.