Fura-8™ Ratiometric Calcium Indicators

In this issue

Fura-8™ Ratiometric Calcium Indicators
Non-Radioactive Glucose Uptake Assays
Multicolor Live or Dead™ Viability Assays for Flow Cytometry
Colorimetric Quantitation of Ammonia
Fluorimetric Quantitation of Formaldehyde
Fluorimetric Quantitation of Lactate Dehydrogenase
Fluorimetric Measurement of Glucose-6-Phosphate
Detection of Reactive Oxygen Species (ROS) Using Multicolor ROS Brite™ Reagents
Fluo-8® Green Calcium Indicators The Brightest Ca2+ Signal at 488 nm Excitation
Reporter Gene Analysis Gaussia Luciferase Reporter Gene Assay
Reporter Gene Analysis Firefly Luciferase Reporter Gene Assay
iFluor™ 594, a New Bright Fluorescent Labeling Dye an Excellent Replacement to Texas Red®, DyLight™ 594 and Alexa Fluor® 594 Dyes
trFluor™ Fluorescent Labeling Dyes and Their Bioconjugates *Optimized for TR-FRET Applications*
ReadiLink™ iFluor™ Antibody Labeling Kits

AssayWise Letters 2013, Vol. 2(1)
cover

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Fluorescence excitation spectra of Fura-8™ in the presence of 0 to 39 µM free Ca²⁺.

ATP dose responses in CHO-K1 cells measured with Fura-2 AM and Fura-8™ AM respectively. CHO-K1 cells were seeded overnight at 40,000 cells/100µL/well in a Costar black wall/clear bottom 96-well plate. The cells were incubated with Fura-2 AM and Fura-8™ AM calcium assay dye-loading solution respectively for 1 hour at room temperature. ATP (50 µL/well) was added by FlexStationR.

Although Fura-2 has been widely used as the preferred excitation ratioable calcium indicator, it has certain limitations, e.g., lower sensitivity compared to the single wavelength calcium dyes such as Fluo-8^® and Cal-520™. AAT Bioquest has recently developed Fura-8™ to improve the calcium response of Fura-2. As demonstrated in Figures 1.1 and 1.2, Fura-8™ AM is more sensitive to calcium than Fura-2 AM. In addition, Fura-8™ has its emission shifted to longer wavelength (Em = 525 nm). Fura-8™ might be also used for the flow cytometric analysis of calcium in cells due to its excellent excitation at 405 nm that perfectly matches the violet laser line of flow cytometer.

Key Features of Fura-8™

Fura-8™ responses to calcium the same way as Fura-2 does
Red-shifted dual excitation wavelengths (354 nm/415 nm)
Better excited at 405 nm for flow cytometric applications
Compatible with common filter sets
Higher signal/background ratio than that of Fura-2

Table 1. Product Ordering Information for Ratiometric Calcium Indicators

Cat No. ▲ ▼	Product Name ▲ ▼	Ex (nm) ▲ ▼	Em (nm) ▲ ▼	Kd(nm) ▲ ▼	Unit Size ▲ ▼
21054	BTC, AM CAS 176767-94-5	401	529	7,000	1 mg
21053	BTC, tetrapotassium salt CAS 216453-54-2	401	529	7,000	1 mg
21021	Fura-2, AM UltraPure Grade CAS 108964-32-5	363	512	145	1 mg
21025	Fura-2, pentapotassium salt CAS 113694-64-7	363	512	145	1 mg
21026	Fura-2, pentasodium salt	363	512	145	1 mg
21055	Fura-8™, AM	354	525	260	1 mg
21056	Fura-8™, AM	354	525	260	10x50 ug
21057	Fura-8™, pentapotassium salt	354	525	260	1 mg
21058	Fura-8™, pentasodium salt	354	525	260	1 mg
21032	Indo-1, AM UltraPure Grade CAS 112926-02-0	346	475	230	1 mg
21040	Indo-1, pentapotassium salt CAS 132319-56-3	346	475	230	1 mg
21044	Indo-1, pentasodium salt	346	475	230	1 mg
21050	Quin-2, AM CAS 83104-85-2	353	495	60	1 mg
21052	Quin-2, tetrapotassium salt CAS 149022-19-5	353	495	60	5 mg

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