TABLE 1.
Summary of physicochemical properties of commercially available tetrazolium-based dyes.
| Short name | Full name | Tetrazolium solubility | Absorb. coef. (reduced formazan) cm–1⋅M–1 | Redox intermediate | Formazan solubility |
| TTC | Triphenyl tetrazolium chloride | 50 mg/ml | 14,320 (sigma) | Not required | Insoluble |
| MTT | Thiazolyl blue tetrazolium bromide | 5 mg/ml | 13,000–16,900 (578 nm) | Not required | Insoluble |
| INT | Iodonitrotetrazolium chloride | 4 mg/ml | 12,000 (480–490 nm) | Not required | Insoluble |
| CTC | 5-Cyano-2,3-di-(p-tolyl)tetrazolium chloride | 15 mg/ml | NA Fluorescent compound | Not required | Insoluble |
| NBT | Nitroblue tetrazolium | 10 mg/ml | 12,300 (580 nm) | Not required | Insoluble |
| XTT | 2,3-Bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide inner salt | 2.5 mg/ml | 21,600–23,800 (470–475 nm) | Recommended | Soluble |
| MTS | MTS(5-(3-carboxymethoxyphenyl)-2(4,5,-dimethyl- thiazolyl)-3-(4 sulfophenyl)tetrazolium inner salt | 2.0 mg/ml | 26,900 (490 nm) | Recommended | Soluble |
| WST-1 | 2-(4-Iodophenyl)-3- (4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium | 10 mg/ml | 37,000 (438 nm) | Required | Soluble |
| WST-3 | 2-(4-Iodophenyl)-3-(2,4-dinitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium | 10 mg/ml | 30,000 (433 nm) | Required | Soluble |
| WST-8 | 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium | 50 mg/ml (H2O) 10 mg/ml (DMSO) | 30,7000 (460 nm) | Required | Soluble |
Data were compiled from the following references and websites: Sutherland and Learmonth (1997); Berridge et al. (2005); Grela et al. (2018); www.sigmaaldrich.com, www.interchim.com, www.medchemexpress.com, www.abcam.com. DMSO, dimethyl sulfoxide; NA, not applicable.