Table 15.1 Esterase substrates for cell viability studies.

Esterase Substrate (Cat. No.) Properties in Cells pKa of Product *
BCECF AM (B1150, B1170, B3051)
  • Quite well retained
  • Released during cytolysis
  • pH-sensitive fluorescence
7.0
Calcein AM (C1430, C3099, C3100MP)
  • Quite well retained
  • Released during cytolysis
  • Not as pH-sensitive as BCECF
5
Carboxyeosin diacetate, succinimidyl ester (CEDA, SE; C22803; Assays for Cell Enumeration, Cell Proliferation and Cell Cycle—Section 15.4)
  • Well retained by reaction with amines
  • Useful for DAB photoconversion
  • Phosphorescent
<5 †
Carboxy-2',7'-dichlorofluorescein diacetate (carboxy-DCFDA, C369)
  • Moderately well retained
  • Not as pH-sensitive as CFDA
4.8
Carboxyfluorescein diacetate (5(6)-CFDA, C195)
  • Moderately well retained
  • pH-sensitive fluorescence
6.4
Carboxyfluorescein diacetate, acetoxymethyl ester (5-CFDA, AM; C1354)
  • Easier to load than CFDA yet yields the same product upon hydrolysis
  • pH-sensitive fluorescence
6.4
Carboxyfluorescein diacetate, succinimidyl ester (5(6)-CFDA, SE; C1157; Assays for Cell Enumeration, Cell Proliferation and Cell Cycle—Section 15.4)
  • Well retained by reaction with amines
  • Not completely released during cytolysis
  • pH-sensitive fluorescence
6.4 †
CellTracker Green CMFDA (CMFDA; C2925, C7025)
  • Well retained by reaction with thiols
  • Not completely released during cytolysis
  • pH-sensitive fluorescence
6.4 †
Chloromethyl SNARF-1, acetate (C6826)
  • Well retained by reaction with thiols
  • Not completely released during cytolysis
  • Long-wavelength, pH-sensitive fluorescence
7.5 †
Fluorescein diacetate (F1303)
  • Poorly retained
  • pH-sensitive fluorescence
  • Inexpensive
6.4
Oregon Green 488 carboxylic acid diacetate (carboxy-F2FDA, O6151)
  • Moderately well retained
  • Not as pH-sensitive as CFDA
4.7
* Approximate pKa values in aqueous solvents. The actual pKa of the indicator will vary somewhat depending upon experimental conditions. † pKa of the unconjugated hydrolysis product; after conjugation to an intracellular amine or thiol, the actual pKa value may be different.

For Research Use Only. Not for use in diagnostic procedures.