pHrodo™ Red Phagocytosis Particle Labeling Kit for Flow Cytometry - FAQs

I am performing a phagocytosis assay of macrophages engulfing pHrodo-labeled bacteria. What do you recommend for fixation after the phagocytosis?

pHrodo is relatively non-fluorescent until it enters the acidic phagosome, at which point its fluorescence increases. If you fix the sample, the pHrodo will only reflect the pH of the buffer the cells are in, and not the pH of the phagosome. For this reason, we do not recommend fixing samples. If you want to see how many cells engulfed the labeled bacteria, fix the cells and then place the fixed cells in an acidic buffer for the assay.

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