Invitrogen™ Molecular Probes™ Rhod dextran, Potassium Salt, 10,000 MW, Anionic (High-Affinity Version)

Labeled calcium indicators are molecules that exhibit increase in fluorescence upon binding Ca²⁺. They have uses in many calcium signaling investigations, including measuring Ca²⁺ in cells and tissues that have high levels of autofluorescence and also for detecting Ca²⁺ release generated by photoreceptors and photoactivatable chelators.

• Rhod coupled to 10,000 MW dextran can be dissolved in water at concentrations up to 20% w/v (200μg/uL) and introduced via patch pipet, microinjection, or Influx™ pinocyte-loading reagent
• Fluorescence signal from these cells is generally measured using fluorescence microscopy
• Dextran forms of calcium indicators show a dramatic reduction in both leakage and compartmentalization compared to the AM ester forms
• Label (Ex/Em of Ca²⁺-bound form): Rhod (552/581nm)
• Fluorescence intensity increase upon binding Ca²⁺: >100 fold
• K_d for Ca²⁺ in the absence of Mg²⁺, in buffer: approximately 750nM
• Exhibit fluorescence increase upon binding Ca²⁺ with little shift in wavelength
• In addition, BAPTA-based indicators such as these bind various heavy metal cations (e.g., Mn²⁺, Zn²⁺, Pb²⁺) with substantially higher affinity than Ca²⁺
• Perturbations to calcium measurements caused by presence of these ions can be controlled using the heavy metal-selective chelator TPEN

Calcium Detection, Cell Analysis, Cell Viability, Proliferation and Function, Ionic Homeostasis and Signaling