FluoriCa-8 AM, green fluorescent calcium indicator (LP3391)

FluoriCa-8 AM is a cell-permeable Ca2+-indicator that is metabolized by intracellular esterase, leading to a bright green fluorescent signal upon Ca2+-binding (excitation/emission λ at 490/514 nm). FluoriCa-8 AM is used for visualization and quantifying intracellular Ca2+. It is well suited for fluorometric and imaging applications such as microscopy, flow cytometry, spectrofluorometry, and fluorometric high-throughput microplate screening assays. FluoriCa-8 AM is similar in structure and spectral properties to the Ca2+ indicators Fluo-3 AM and Fluo-4 AM but has the brightest fluorescence compared to them (two times brighter than Fluo-4 and four times brighter than Fluo-3). The Kd of FluoriCa-8 AM for Ca2+ is about 389 nM. With its highest fluorescence intensity, FluoriCa-8 AM is ideal for applications where the concentration of dye loaded into cells is required to be minimized. Unlike Fluo-3 AM and Fluo-4 AM, which require cells to be incubated at 37 °C, FluoriCa-8 AM can be loaded into cells at room temperature. As FluoriCa-8 AM does not covalently bind to cellular components, it may be actively effluxed from the cell by organic anion transporters. In vivo cell imaging with FluoriCa-8 AM is usually performed within one or two hours after loading, but the dye can be re-loaded to cells if it is needed. To determine the cellular localization of the dye, FluoriCa-8 AM can be fixed in situ with EDC/EDAC and counterstained immunochemically using anti-BAPTA antibodies. FluoriCa-8 AM has low solubility in the water. It is recommended to prepare 1 mM stock solution in labeling grade DMSO prior to cell loading. Use the final concentration of 1-5 μM and incubation at RT for 15-60 min as a start point of your protocol. FluoriCa-8 AM solutions in DMSO may be stored at -20 °C for up to 2 months.