SeTau Lifetime Labels

Fluorescent labels with long fluorescence lifetimes

Excitation Light Sources Characteristics Characteristics
Product Number
(Specs Sheet)
Product Name
(Product Info)
Target Group 380 405 436 488 532 594 635 650 680 700 750 780 Medium λ abs
[nm]
ε
[M –1
cm–1]
λ em
[nm]
QY
[%]
FLT
[ns]
Medium λ abs
[nm]
ε
[M–1
cm–1]
λ em
[nm]
QY
[%]
FLT
[ns]
Buy
                               
K1-204
K1-204
SeTau-380-NHS
SeTau-380-NHS
NH2 Water 270 23,800 480 56 32.5 BSA, D/P=1 383 23,800 468 44 30.6
K7-547
K7-547
SeTau-405-NHS
SeTau-405-NHS
NH2 PB 7.4 405 13,800 518 80 9.3 IgG, D/P=8 405 13,800 518 19 8.4
K7-567
K7-567
SeTau-405-Azide
SeTau-405-Azide
triple-CC PB 7.4 405 13,800 518 80 9.3 EtOH 391 15,000 498 55 8.5
K7-545
K7-545
SeTau-425-NHS
SeTau-425-NHS
NH2 PB 7.4 425 4,200 545 39 26.2 BSA, D/P=1 427 4,200 528 16 26.2
K9-4119
K9-4119
SeTau-665-NHS
SeTau-665-NHS
NH2 PB 7.4 664 160,000 712 53 3.1 IgG, D/P=1.5 662 716 46
K9-4142
K9-4142
SeTau-647-di-NHS
SeTau-647-di-NHS
NH2 PB 7.4 650 200,000 694 65 3.2 IgG, D/P=0.5 649 200,000 691 58 3.2
K9-4148
K9-4148
SeTau-647-Maleimide
SeTau-647-Maleimide
SH PB 7.4 648 200,000 692 45 3.2 PB 7.4 648 200,000 692 45 3.2
K9-4149
K9-4149
SeTau-647-NHS
SeTau-647-NHS
NH2 PB 7.4 649 200,000 695 61 3.2 IgG, D/P=1 648 200,000 694 59 3.3
K9-4169
K9-4169
SeTau-670-NHS
SeTau-670-NHS
NH2 PB 7.4 673 275,000 694 36 1.6 IgG D/P = 4 672 693 14 1.75
K7-548
K7-548
SeTau-405-Maleimide
SeTau-405-Maleimide
SH PB 7.4 405 13,800 518 51 9.1 EtOH 391 15,000 498 32 8.5
K7-544
K7-544
SeTau-425-Maleimide
SeTau-425-Maleimide
SH PB 7.4 425 4,200 545 39 26.2 PB 7.4 425 4,200 545 39 26.2
K9-4179
K9-4179
SeTau-680-NHS
SeTau-680-NHS
NH2 PB 7.4 683 295,000 705 58 2.9 IgG D/P=1 682 703 47 3.1

 

Short-Wavelength SeTau Lifetime Dyes

These labels with longer lifetimes in the range between 9 and 32 ns are excitable in the UV or blue region and are well-suited as polarization probes for the measurement of high MW analytes (small proteins) or for lifetime-based applications. They exhibit long lifetimes that are not environment sensitive.

SeTau-380-NHS is a reactive dye with a with a large Stokes’ shift of 210 nm and a fluorescence lifetime of 32.5 ns in water. Exc./Em. max: 270/480 nm.

SeTau-405-NHS is a dye with a fluorescence lifetime of 9 ns in PB7.4 that is well suited for excitation with the blue 404 nm diode laser. Because of its large Stokes’ shift of more than 110 nm, the quenching tendency upon labeling to proteins is very low. Importantly the longer lifetime of 9 ns in aqueous media is making it also a valuable label for studying of protein hydrodynamics (fluorescence polarization measurements). It is a good alternative for Pacific Orange to be used with Pacific Blue in flow cytometry applications. Compatible with the Fluorescein emission filter. Exc./Em. max: 405/518 nm.

SeTau-425-NHS with a fluorescence lifetime of 26 ns in PB7.4 was used to measure high-molecular-weight analytes such as BSA directly in an FP assay (more under Fluorescence Polarization). Importantly the FLT of these labels does not change upon covalent attachment to proteins or other analytes. For more information we refer you to Lifetime Applications.
 

Frequency responses (phase and modulation) for SeTau-380, SeTau-405 and SeTau-425
Frequency responses (phase and modulation)
for SeTau-380, SeTau-405 and SeTau-425
Intensity decays for SeTau-380, SeTau-405 and SeTau-425
Intensity decays for SeTau-380, SeTau-405 and SeTau-425

 

Long-Wavelength SeTau Lifetime Dyes

While the fluorescence lifetime (FLT) of organic dyes is a reporting strategy for molecular imaging and recently even for flow cytometry, fluorescent dyes emitting in the NIR have very short lifetimes in the range between 0.5 to 1.5 ns. Importantly, longer lifetimes of NIR dyes (in the order of 3 ns) were only measured in presence of BSA or in organic solvents. In addition most of these dyes are neither soluble in aqueous media nor can be conjugated to biomolecules and therefor are not suitable as labels [28].

SETA BioMedicals has developed several reactive, ionic, water-soluble squaraine rotaxanes with emission in the NIR region that have «longer» fluorescent lifetimes ~ 3 ns (see below), making them in particular suitable as labels for lifetime-based imaging applications in the red and NIR wavelength region.

The NIR squaraine rotaxane dye SeTau-680 has a lifetime of 2.9 ns in PB7.4, while the fluorescent lifetimes of comparable, conventional NIR labels e.g. Alexa 680 or Alexa 700 are in the order of 1 - 1.2 ns.

SeTau-647-maleimide with a lifetime of 3.2 ns in PB7.4 has been successfully used in the studies of the mechanism of muscle contractions using FCS, specifically fluorescence lifetime correlation spectroscopy (FLCS), fluorescence lifetime and time-resolved fluorescence polarizations methods [27].

SeTau 680-NHS  (Φ = 0.58, ε = 215,000 and Φ. ε = 124,700) with a similar absorption and emission as Alexa 680 is twice as bright as Alexa 680 (Φ = 0.36,  ε = 183,000 and Φ. ε = 65,880) and exhibits a lower quenching tendency when labeled to biomolecules. Exc./Em. max of IgG-conjugates: 682/703 nm. Its lifetime is 2.9 ns in PB7.4.

SeTau-665-NHS is a hydrophilic, mono-reactive squaraine rotaxane label for biomolecules. It is very bright (Φ = 0.53,  ε = 161,000 and Φ. ε = 83,330) with a large Stokes' shift of 48 nm and a similar emission as Alexa 700 (Φ = 0.25,  ε = 205,000 and Φ. ε = 51,250) but SeTau-665 is a factor of ~ 1.6 times brighter. It is optimally excited with a 665 nm diode laser. This dye also holds the record for 2PECSs of fluorescent labels with >8500 GM at 900 nm. Lifetime: 3.2 ns in PB7.4. Exc./Em. max of IgG-conjugates: 665/712 nm.

SeTau-647-NHS is a hydrophilic, mono-reactive squaraine rotaxane label for biomolecules. Compared to Cy5 (Φ = 0.27,  ε = 250,000 and Φ. ε = 67,500) or Alexa 647 (Φ = 0.33,  ε = 239,000 and Φ. ε = 78,870) it is an extremely bright label (Φ = 0.53,  ε = 200,000 and Φ. ε = 106,000) with a large Stokes' shift of 46 nm. It is a highly ozone- and photostable dye that is optimally excited with the 647 nm spectral line of the Krypton-Argon laser. Its lifetime is 3.2 ns in PB7.4. Exc./Em. max for conjugates: 649/695 nm. 

 

Frequency responses of SeTau-647-NHS in aqueous buffer solution pH 7.4
Frequency responses of SeTau-647-NHS in
aqueous buffer solution pH 7.4
Intensity decays of SeTau-647-NHS in aqueous buffer solution pH 7.4 in comparison to Alexa 647
Intensity decays of SeTau-647-NHS in aqueous
buffer solution pH 7.4 in comparison to Alexa 647

 

Additional dyes for lifetime applications can be found here.

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