Search Thermo Fisher Scientific
Search Thermo Fisher Scientific
Related Tables
Related Technical Notes
Get Chapter Downloads from The Molecular Probes Handbook, 11th edition |
Fluorescent probes that show a spectral response upon binding Ca2+ have enabled researchers to investigate changes in intracellular free Ca2+ concentrations using fluorescence microscopy, flow cytometry and fluorescence spectroscopy. The properties and applications of these fluorescent indicators—most of which are derivatives of the Ca2+ chelators EGTA, APTRA and BAPTA —have been extensively reviewed. Several earlier reviews of these ion indicators also contain useful technical information.
We discuss chemical Ca2+ indicators according to their excitation requirements in Fluorescent Ca2+ Indicators Excited with UV Light—Section 19.2 and Fluorescent Ca2+ Indicators Excited with Visible Light—Section 19.3, and their high-molecular weight conjugates are described in Fluorescent Ca2+ Indicator Conjugates—Section 19.4. Protein-based Ca2+ sensors are discussed in Protein-Based Ca2+ Sensors—Section 19.5.
We offer the widest selection of fluorescent indicators available for detecting changes in intracellular Ca2+ over the range of <50 nM to >50 µM (Summary of Molecular Probes fluorescent Ca2+ indicators—Table 19.1). As the primary suppliers of fura-2, indo-1, fluo-3 (), fluo-4 and rhod-2, we also offer many specialized indicators for intracellular Ca2+. Our fura-4F, fura-6F and fura-FF indicators provide increased response sensitivity to intracellular Ca2+ concentration in the 0.5–5 µM range, as compared with fura-2. The fluo-3, fluo-4, Oregon Green 488 BAPTA, Calcium Green, X-rhod-1 and Fura Red indicators and their variants enable Ca2+ detection in confocal microscopy and high-throughput G protein–coupled receptor (GPCR) screening applications. In addition, we offer indicators that are conjugated to high– or low–molecular weight dextrans for improved cellular retention and less compartmentalization (Fluorescent Ca2+ Indicator Conjugates—Section 19.4). We strive to provide the highest-purity indicators available anywhere. The AM ester forms of most of our indicators are typically at least 95% pure by HPLC analysis, although purity often exceeds 98%. Furthermore, the AM esters of many of the Ca2+ and Mg2+ indicators are available in sets of 50 µg for more convenient handling and reduced risk of deterioration during storage. For high-throughput screening applications, fluo-4 AM is offered in special multi-unit packages (F14202), as well as in application-specific Fluo-4 NW and Fluo-4 Direct Calcium Assay Kits (Fluorescent Ca2+ Indicators Excited with Visible Light—Section 19.3).
A number of factors should be considered when selecting a fluorescent Ca2+ indicator, some of which are summarized in Summary of Molecular Probes fluorescent Ca2+ indicators—Table 19.1 and include the following:
Intracellular calibration of Ca2+ indicators may be achieved either by manipulating Ca2+ levels inside cells using an ionophore or by releasing the indicator into the surrounding medium of known Ca2+ concentration via detergent lysis of the cells. We also offer several compounds and buffers for measuring and manipulating intracellular and extracellular Ca2+. These products, which are discussed in Chelators, Calibration Buffers, Ionophores and Cell-Loading Reagents—Section 19.8, include caged Ca2+ reagents and caged chelators (NP-EGTA, DMNP-EDTA and diazo-2), as well as Calcium Calibration Buffer Kits, BAPTA-derived buffers, ion-selective chelating polymers (Calcium Sponge) and the important Ca2+ ionophores ionomycin, A-23187 and its nonfluorescent analog, 4-bromo A-23187. Reagents for probing Ca2+ regulation and second messenger activity are described in more detail in Probes for Signal Transduction—Chapter 17. Our reagents for the study of Ca2+ channels are described in Probes for Ion Channels and Carriers—Section 16.3.
For Research Use Only. Not for use in diagnostic procedures.