What does Fura-2 measure?

Fura-2 is a ratiometric and sensitive indicator dye for measuring intracellular calcium. Since its introduction in 1985, fura-2 has been cited in thousands of papers that describe its applications in a wide variety of cells.

Why Fura-2 is unable to cross cell membranes?

Calcium indicators are unable to cross lipid membranes due to their nature, making necessary the use of physical or chemical methods to load them inside the cell. This is the case of Indo-1 AM and Fura-2 AM, which are fluorescent and calcium insensitive.

Is Fura-2 a protein?

More recently, genetically-encoded calcium indicators based on spectral variants of the green fluorescent protein, such as Cameleons, have supplemented the use of Fura-2 and other small molecule dyes for calcium imaging, but Fura-2 remains faster….Fura-2.

Is fluo 4 a ratiometric?

Fluo-4 is a fast, high-affinity Ca2+-dye that has been widely used in live cell imaging to determine fast changes in Ca2+-homeostasis. Since Fluo-4 is a non-ratiometric dye however, its fluorescence intensity strongly depends on the absolute dye concentration in addition to environmental parameters.

How is the fluorescence of Fura-2 measured?

Usually, the intensity of fluorescence induced by 340 nm and 380 nm excitation and emitted at 510 nm is measured, and therefore Fura-2 is a ratiometric dye. The ratio of F340/F380 fluorescence intensity is proportional to and in practice commonly used to indicate the cytoplasmic Ca 2 + level.

What is the excitation spectrum of Fura-2 dye?

In addition, fura-2 is bright enough to permit measurements at intracellular concentrations of dye unlikely to cause significant Ca 2+ buffering or damping of Ca 2+ transients. Figure 1: Fluorescence excitation spectra of fura-2 ( F1200 , F6799) in solutions containing 0–39.8 µM free Ca2+.

What is the emission peak of Fura-2 am?

One of the most common calcium indicators is Fura-2, which has an emission peak at 505 nM and changes its excitation peak from 340 nm to 380 nm in response to calcium binding. Here we describe the use of Fura-2 to measure intracellular calcium elevations in neurons and other excitable cells.

What is the principle of use of Fura-2?

The principle using Fura-2 is based on the shift of its fluorescence excitation spectrum toward shorter wavelength upon Ca 2 + binding ( Grynkiewicz, Poenie, & Tsien, 1985; Zanin, Lidron, Rizzuto, & Pallafacchina, 2019 ).