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Oxazole Blue Homodimer (POPO™-1), 1 mM in DMSO

Oxazole Blue Homodimer, also known as POPO™-1, is a blue-fluorescent, cell-impermeant nucleic acid stain that can be used to stain dead or fixed cells.

Product Attributes

Apoptosis/viability marker

Dead cell stain

For live or fixed cells

For fixed cells, For live/intact cells

Detection method/readout

Fluorescence microscopy, Flow cytometry

Probe cellular localization

Nucleus & cytoplasm

Assay type/options

No-wash staining, Real-time imaging

Cell permeability

Membrane impermeant



CAS number



433/457 nm (with DNA)

Catalog #
100 uL (1 mM in DMSO)
Clear selection
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Product Description

Oxazole Blue Homodimer, also known as POPO™-1, is a blue-fluorescent, cell-impermeant, high-affinity carbocyanine dimeric nucleic acid stain. The dye is essentially non-fluorescent in the absence of nucleic acids but exhibits strong excitation/emission maxima 433/457 nm when bound to nucleic acids. In addition, the dye is non-cytotoxic and may be used for long-term monitoring of viability in cell cultures.

  • Dimeric nucleic acid stain
  • Cell-impermeant
  • λExEm (with DNA) = 433/457 nm
  • Supplied at 1 mM in DMSO
  • C41H54I4N6O2
  • MW: 1170
  • CAS number: 169454-15-3

See the table below for other chemical equivalents of Thermo Fisher Scientific’s branded dead-cell selective nucleic acid dyes.

Biotium also offers unique NucSpot® Nuclear Stains for bright and specific nuclear staining in dead or fixed cells. The stains are available in a wide range of colors from green to near-IR. See our Cellular Stains Selection Guide and Cellular Stains Table for more information on other nuclear stains we offer.


Equivalent to

Color (Ex/Em)

Catalog No.

Oxazole Blue, 1 mM in DMSOPO-PRO™-1Blue (434/457 nm) 40091
Oxazole Blue Homodimer, 1 mM in DMSOPOPO™-1Blue (433/457 nm) 40093
Oxazole Yellow, 1 mM in DMSOYO-PRO®-1Green (491/506 nm) 40089
Oxazole Yellow Homodimer, 1 mM in DMSOYOYO®-1Green (491/508 nm) 40090
TO Iodide, 1 mM in DMSOTO-PRO®-1Green (515/531 nm)40088
Thiazole Orange Homodimer, 1 mM in DMSOTOTO®-1Green (514/531 nm)40079
Oxazole Red, 1 mM in DMSOYO-PRO®-3Far-red (613/629 nm)40105
Oxazole Red Homodimer, 1 mM in DMSOYOYO®-3Far-red (612/631 nm)40106
Thiazole Red, 1 mM in DMSOTO-PRO®-3Far-red (642/657 nm)40087
Thiazole Red Homodimer, 1 mM in DMSOTOTO®-3Far-red (642/661 nm)40080
YOYO, YO-PRO, POPO, PO-PRO, TOTO, and TO-PRO are trademarks and registered trademarks of Thermo Fisher Scientific.

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