Labeled calcium indicators are molecules that exhibit an increase in fluorescence upon binding Ca
2+. They have uses in many calcium signaling investigations, including measuring Ca
2+ in cells and tissues that have high levels of autofluorescence and also for detecting Ca
2+ release generated by photoreceptors and photoactivatable chelators. Cells may be loaded with the AM ester forms of these calcium indicators by adding the dissolved indicator directly to dishes containing cultured cells. The fluorescence signal from these cells is generally measured using fluorescence microscopy.
Learn more about ion indicators including calcium, potassium, pH, and membrane potential indicators ›Calcium Indicator (AM Ester) Specifications:
• Label (Ex/Em of Ca2+–bound form): X-rhod-1 (580/602 nm)
• Fluorescence intensity increase upon binding Ca2+: >100 fold
• Kd for Ca2+ in the absence of Mg2+, in buffer: ∼700 nM
• Exhibit fluorescence increase upon binding Ca2+ with little shift in wavelengthUsing TPEN to Control Heavy Metal Cations In addition, BAPTA-based indicators such as these bind various heavy metal cations (e.g., Mn
2+, Zn
2+, Pb
2+) with substantially higher affinity than Ca
2+. Perturbations to calcium measurements caused by presence of these ions can be controlled using the heavy metal-selective chelator
TPEN.
More Choices for Fluorescent Calcium Indicators We offer a large selection of Molecular Probes™ calcium indicators for use in various experimental scenarios, for example dextran versions for reduced leakage and compartmentalization and BAPTA conjugates for detecting high-amplitude calcium transients. For more information, review
Fluorescent Ca2+ Indicators Excited with Visible Light—Section 19.3 in the Molecular Probes™ Handbook.
For UV-excitable Ca
2+ indicators, protein-based Ca
2+ indicators, conjugates of Ca
2+ indicators, and for fluorescence-based indicators of other metal ions (i.e., Mg
2+, Zn
2+) review
Indicators for Ca2+, Mg2+, Zn2+ and Other Metal Ions—Chapter 19 in the Molecular Probes™ Handbook.
For Research Use Only. Not for human or animal therapeutic or diagnostic use.
For Research Use Only. Not for use in diagnostic procedures.