Description
Optical properties
λ abs = 646 nm
ε max = 1.5×10 5 M -1 cm -1
λ fl = 664 nm
n fl = 65 %
τ fl = 3.5 ns
CF 260 = ε 260 /ε max = 0.04
CF 280 = ε 280 / ε max = 0.03
ATTO 647N belongs to a new generation of fluorescent labels for the red spectral region. Characteristic features of the label are strong absorption, high fluorescence quantum yield, high thermal and photo-stability, and exceptionally high stability towards atmospheric ozone. Thus ATTO 647N is highly suitable for single-molecule detection applications and high-resolution microscopy such as SIM, STED etc. Additionally the dye highly qualifies to be applied in flow cytometry (FACS) , fluorescence in-situ hybridization (FISH and many more.
In common with most ATTO-labels, absorption and fluorescence are independent of pH, at least in the range of pH 2 to 11, used in typical applications. The dye is moderately hydrophilic. ATTO 647N is a cationic dye. After coupling to a substrate the dye carries a net electrical charge of +1.
As supplied ATTO 647N consists of a mixture of two isomers with practically identical absorption and fluorescence properties. The fluorescence is excited most efficiently in the range 625 - 660 nm . A suitable excitation source is the 647 nm line of the Krypton-Ion laser or a diode-laser emitting at 650 nm.
