Labeled calcium indicators are molecules whose fluorescence intensity increases upon binding Ca²⁺ ions. Fluo-3 is used in flow cytometric analysis, such as experiments involving photoactivation of cage chelators, second messengers and neurotransmitters, and pharmacological screening at the cellular level, for Ca²⁺ Spatial dynamics imaging. Fluo-4 is an analogue of fluo-3 in which two chlorine substituents are replaced by fluorine, resulting in enhanced fluorescence excitation at a wavelength of 488 nm and therefore higher fluorescence signal levels. These can be transferred using physical methods such as patch pipettes, microinjection, or Influx™ Cell Pinocytosis Loading Reagent A non-cell permeable salt form of the indicator is loaded into the cells. These indicators can be used for fluorescence and confocal microscopy analysis, flow cytometric analysis, and microplate screening applications.

Learn more about ionic indicators including calcium, potassium, pH and membrane potential indicators›

Calcium Indicator (Non-Cell Permeable Salt) Specifications :
• Label (Ca²⁺–conjugated form Ex/Em): Fluo-4 (494/516 nm)
• Conjugated Ca²⁺ Post-fluorescence intensity increase: >100 times
• K_d bound to Ca²⁺ in buffer: ∼335 nM
• Binding Ca< After sup>2+, the fluorescence increases and the wavelength changes slightly

Using TPEN to control heavy metal cations
In addition, BAPTA-based indicators can Binds various heavy metal cations (such as Mn²⁺, Zn²⁺, Pb⁺²) with much higher affinity than Ca^{2 +}. The heavy metal selective chelator TPEN can be used to control perturbations in calcium measurements caused by these ions.

More choices of fluorescent calcium indicators
We provide a large number of Molecular Probes™ calcium indicators for use in various experimental scenarios. For more information, see Visible light excited fluorescent Ca²⁺ indicators—Chapter 19.3 section.

For UV excited Ca²⁺ indicators, protein-based Ca²⁺ indicators, Ca²⁺ indicators Conjugates of reagents and fluorescent indicators of other metal ions (i.e. Mg²⁺, Zn²⁺), please see Ca²⁺, Mg²⁺, Zn²⁺, and other metal ion indicators—Chapter 19.

For scientific research use only. Not for therapeutic or diagnostic use in humans or animals.