Leica, AD-633-61, ATTO 633 Streptavidin Fluorescent Label 1 mg

Optical properties
λ abs = 630 nm
ε max = 1.3×10 5 M -1 cm -1
λ fl = 65 1nm
n fl = 64 %
τ fl = 3.3 ns
CF 260 = ε 260 /ε max = 0.04
CF 280 = ε 280 / ε max = 0.05
ATTO 633 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, and high thermal and photo-stability. Thus ATTO 633 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. ATTO 633 is a cationic dye. After coupling to a substrate the label carries a net electrical charge of +1.
The label is moderately hydrophilic. Its fluorescence is excited most efficiently in the range 610 - 645 nm . A suitable excitation source for ATTO 633 is the 633 nm line of the He:Ne laser or a diode-laser emitting at 635 nm.