Fura-2 (Ca2+free)
Fura-2 (Ca2+free) (Ex-Max 368 nm/Em-Max 513 nm)
Fura-2, AM is a cell-permeant ratiometric calcium indicator. When Fura-2, AM loads a cell and is intracellularly hydrolyzed, it exhibits an increase in excitation efficiency at 336nm but not at 368nm. This increases the emission intensity monitored at ~510nm when bound to calcium while excited by 336nm energy while the reduced intensity can be monitored at the ~510nm emission off the 368nm excitation. Because of the unique spectral characteristics, this probe is most commonly used in fluorescence microscopy.
Excitation & emission spectra
Key facts
- Excitation maximum
- 368 nm
- Emission maximum
- 510 nm
- Optimal filter
- 525/50
Fura-2 (Ca2+free) has an excitation maximum at 368 nm and an emission maximum at 510 nm, a Stokes shift of 142 nm.
Frequently asked questions
- What is Fura-2 (Ca2+free)?
- Fura-2, AM is a cell-permeant ratiometric calcium indicator. When Fura-2, AM loads a cell and is intracellularly hydrolyzed, it exhibits an increase in excitation efficiency at 336nm but not at 368nm. This increases the emission intensity monitored at ~510nm when bound to calcium while excited by 336nm energy while the reduced intensity can be monitored at the ~510nm emission off the 368nm excitation. Because of the unique spectral characteristics, this probe is most commonly used in fluorescence microscopy.
- What filter should I use to detect Fura-2 (Ca2+free)?
- A 525/50 filter captures the peak of the Fura-2 (Ca2+free) emission near 510 nm with minimal spillover.