TWO-PRO™ 3 [equivalent to TO-PRO®-3] *5 mM DMSO Solution* *CAS 157199-63-8*
Ordering information
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Additional ordering information
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Quotation | Request |
International | See distributors |
Shipping | Standard overnight for United States, inquire for international |
Physical properties
Molecular weight | 671.42 |
Solvent | DMSO |
Spectral properties
Extinction coefficient (cm -1 M -1) | 1020001 |
Excitation (nm) | 642 |
Emission (nm) | 657 |
Quantum yield | 0.111 |
Storage, safety and handling
H-phrase | H303, H313, H340 |
Hazard symbol | T |
Intended use | Research Use Only (RUO) |
R-phrase | R20, R21, R68 |
Storage | Freeze (< -15 °C); Minimize light exposure |
UNSPSC | 41116134 |
Overview | ![]() ![]() |
CAS 157199-63-8 | Molecular weight 671.42 | Extinction coefficient (cm -1 M -1) 1020001 | Excitation (nm) 642 | Emission (nm) 657 | Quantum yield 0.111 |
TWO-PRO™-3 is chemically equivalent to TO-PRO®-3 (TO-PRO® is the trademark of Invitrogen). TWO-PRO™-3 is a carbocyanine dimer with far-red fluorescence similar to Cy® 5 dyes. It is cell-impermeant and easily distinguished from fluorescein and rhodamine as a nuclear counterstain and dead cell indicator. It is non-fluorescent in the absence of nucleic acids, and generates a very bright fluorescence signal upon binding to DNA. TWO-PRO™-3 gives strong and selective nuclear staining in cultured cells and in paraffin sections. Simultaneous labeling with cell-permeable Nuclear Green™ LCS1 dye and cell-impermeant TWO-PRO™-3 can be used to assess cell viability. TWO-PRO™-3 and Nuclear Green™ both have much greater extinction coefficients than that of DNA-bound propidium iodide.
Platform
Fluorescence microscope
Excitation | Cy5 filter set |
Emission | Cy5 filter set |
Recommended plate | Black wall/clear bottom |
Instrument specification(s) | Cy5 filter set |
Example protocol
PREPARATION OF WORKING SOLUTION
TWO-PRO™-3 working solution
Make TWO-PRO™-3 working solution in Hanks with 20 mM Hepes buffer (HH buffer) or buffer of your choice at your desired concentration.Note In initial experiments, it may be best to try several dye concentrations to determine the optimal concentration that yields the desired result. High dye concentration tends to cause nonspecific staining of other cellular structures.
SAMPLE EXPERIMENTAL PROTOCOL
Caution: The following protocol can be adapted for most cell types. Growth medium, cell density, the presence of other cell types and factors may influence staining. Residual detergent on glassware may also affect staining of many organisms, and cause brightly stained material to appear in solutions with or without cells present.
- Grow and treat cells as desired.
- Remove the cell culture medium.
- Add TWO-PRO™-3 working solution (1 to 10 µM) into the cells (either suspension or adherent cells), and stain the cells for 15 to 60 minutes.
- Remove the dye working solution and add HH buffer or buffer of your choice.
- Analyze the cellular staining with a fluorescence microscope using Cy5 filter.
Calculators
Common stock solution preparation
Table 1. Volume of DMSO needed to reconstitute specific mass of TWO-PRO™ 3 [equivalent to TO-PRO®-3] *5 mM DMSO Solution* *CAS 157199-63-8* to given concentration. Note that volume is only for preparing stock solution. Refer to sample experimental protocol for appropriate experimental/physiological buffers.
0.1 mg | 0.5 mg | 1 mg | 5 mg | 10 mg | |
1 mM | 148.938 µL | 744.69 µL | 1.489 mL | 7.447 mL | 14.894 mL |
5 mM | 29.788 µL | 148.938 µL | 297.876 µL | 1.489 mL | 2.979 mL |
10 mM | 14.894 µL | 74.469 µL | 148.938 µL | 744.69 µL | 1.489 mL |
Molarity calculator
Enter any two values (mass, volume, concentration) to calculate the third.
Mass (Calculate) | Molecular weight | Volume (Calculate) | Concentration (Calculate) | Moles | ||||
/ | = | x | = |
Spectrum
Open in Advanced Spectrum Viewer


Spectral properties
Extinction coefficient (cm -1 M -1) | 1020001 |
Excitation (nm) | 642 |
Emission (nm) | 657 |
Quantum yield | 0.111 |
Product Family
Name | Excitation (nm) | Emission (nm) | Extinction coefficient (cm -1 M -1) | Quantum yield |
TWO-PRO™ 1 [equivalent to TO-PRO®-1] *5 mM DMSO Solution* *CAS 157199-59-2* | 515 | 531 | 628001 | 0.251 |
PRO-TAO-3 [equivalent to TO-PRO-3] | 642 | 657 | 102000 | 0.111 |
Images
Citations
View all 1 citations: Citation Explorer
A lysosomal regulatory circuit essential for the development and function of microglia
Authors: Iyer, Harini and Shen, Kimberle and Meireles, Ana M and Talbot, William S
Journal: Science advances (2022): eabp8321
Authors: Iyer, Harini and Shen, Kimberle and Meireles, Ana M and Talbot, William S
Journal: Science advances (2022): eabp8321
References
View all 42 references: Citation Explorer
Daptomycin exerts rapid bactericidal activity against Bacillus anthracis without disrupting membrane integrity
Authors: Xing YH, Wang W, Dai SQ, Liu TY, Tan JJ, Qu GL, Li YX, Ling Y, Liu G, Fu XQ, Chen HP.
Journal: Acta Pharmacol Sin (2014): 211
Authors: Xing YH, Wang W, Dai SQ, Liu TY, Tan JJ, Qu GL, Li YX, Ling Y, Liu G, Fu XQ, Chen HP.
Journal: Acta Pharmacol Sin (2014): 211
Quantification of Candida albicans by flow cytometry using TO-PRO((R))-3 iodide as a single-stain viability dye
Authors: Kerstens M, Boulet G, Pintelon I, Hellings M, Voeten L, Delputte P, Maes L, Cos P.
Journal: J Microbiol Methods (2013): 189
Authors: Kerstens M, Boulet G, Pintelon I, Hellings M, Voeten L, Delputte P, Maes L, Cos P.
Journal: J Microbiol Methods (2013): 189
A silicon cell cycle in a bacterial model of calcium phosphate mineralogenesis
Authors: Linton KM, Tapping CR, Adams DG, Carter RD, Shore RC, Aaron JE.
Journal: Micron (2013): 419
Authors: Linton KM, Tapping CR, Adams DG, Carter RD, Shore RC, Aaron JE.
Journal: Micron (2013): 419
Pulsed electromagnetic field affects intrinsic and endoplasmatic reticulum apoptosis induction pathways in MonoMac6 cell line culture
Authors: Kaszuba-Zwoinska J, Chorobik P, Juszczak K, Zaraska W, Thor PJ.
Journal: J Physiol Pharmacol (2012): 537
Authors: Kaszuba-Zwoinska J, Chorobik P, Juszczak K, Zaraska W, Thor PJ.
Journal: J Physiol Pharmacol (2012): 537
Determination of the drug-DNA binding modes using fluorescence-based assays
Authors: Williams AK, Dasilva SC, Bhatta A, Rawal B, Liu M, Korobkova EA.
Journal: Anal Biochem (2012): 66
Authors: Williams AK, Dasilva SC, Bhatta A, Rawal B, Liu M, Korobkova EA.
Journal: Anal Biochem (2012): 66
Transient changes in neuronal cell membrane permeability after blast exposure
Authors: Arun P, Abu-Taleb R, Valiyaveettil M, Wang Y, Long JB, Nambiar MP.
Journal: Neuroreport (2012): 342
Authors: Arun P, Abu-Taleb R, Valiyaveettil M, Wang Y, Long JB, Nambiar MP.
Journal: Neuroreport (2012): 342
A comparison of TO-PRO-1 iodide and 5-CFDA-AM staining methods for assessing viability of planktonic algae with epifluorescence microscopy
Authors: Gorokhova E, Mattsson L, Sundstrom AM.
Journal: J Microbiol Methods (2012): 216
Authors: Gorokhova E, Mattsson L, Sundstrom AM.
Journal: J Microbiol Methods (2012): 216
SOCS-3 antagonizes pro-apoptotic effects of TRAIL and resveratrol in prostate cancer cells
Authors: Horndasch M, Culig Z.
Journal: Prostate (2011): 1357
Authors: Horndasch M, Culig Z.
Journal: Prostate (2011): 1357
The fluorescent dyes TO-PRO-3 and TOTO-3 iodide allow detection of microbial cells in soil samples without interference from background fluorescence
Authors: Henneberger R, Birch D, Bergquist P, Walter M, Anitori RP.
Journal: Biotechniques (2011): 190
Authors: Henneberger R, Birch D, Bergquist P, Walter M, Anitori RP.
Journal: Biotechniques (2011): 190
Preclinical evaluation of novel triphenylphosphonium salts with broad-spectrum activity
Authors: Millard M, Pathania D, Shabaik Y, Taheri L, Deng J, Neamati N.
Journal: PLoS One (2010)
Authors: Millard M, Pathania D, Shabaik Y, Taheri L, Deng J, Neamati N.
Journal: PLoS One (2010)
Application notes
FAQ
What are the commonly used non-fixed cell viability dyes?
Are Cell Navigator® Cell Plasma Membrane Staining Kits suitable for cell culture medium samples?
Are there any alternatives for ethidium bromide in agarose gels?
Are there any alternatives to Cy5?
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Are Cell Navigator® Cell Plasma Membrane Staining Kits suitable for cell culture medium samples?
Are there any alternatives for ethidium bromide in agarose gels?
Are there any alternatives to Cy5?
Are there safer alternatives to ethidium bromide?