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Product Name: SeTau-500-NHS

Product Number:
K9-3162
Target Group:
NH2
Excitation Light Sources:
Medium 1:
PB 7.4
λAb max. [nm]:
502
ε [M–1 cm–1]:
59600
λEm max. [nm]:
567
QY [%]:
43
FLT [ns]:
2.8
Specs Sheet:
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General Data

  • Molecular Mass: 1628.70; 1370.22 (protonated form)
  • Solubility: Water, Alcohol, DMF, DMSO, Acetonitrile
  • Insoluble: Hexane
  • Storage: Store in the absence of light, desiccate, and refrigerate

Description

  • Large Stokes shift, highly stable and bright, water-soluble, amine-reactive label containing one NHS-ester group.
  • Ideal for labeling antibodies, proteins, and other amino-modified biomolecules, including oligonucleotides.
  • Brighter and more photostable replacement for Cy3 and fluorescein-type labels such as Alexa 488 and Alexa 555.
  • Perfectly suited for excitation with 480–505-nm light sources.

Advantages

  • Significantly higher photostability compared to FITC, Alexa 488, or Cy3.
  • Excellent chemical stability against oxidation by peroxides and other reactive oxygen species (ROS).
  • Exceptionally large Stokes shift of >60 nm (much larger than Alexa 488 (494/517) (23 nm), Alexa 555 ex/em:553/568 (15 nm), or Cy3 ex/em:550/565 (15 nm).
  • The large Stokes shift (>60 nm) enables the use of wider filter sets (e.g., 585/15, 535 LP, 560/40, 535 LP), improving measurement sensitivity.
  • Very high fluorescence quantum yield of 40–70% in aqueous media and ~60% for protein and antibody conjugates, which is much higher than Cy3 (QY ~ 4% [1]) or Alexa 555 (QY ~ 10% [2]) in PBS.
  • Longer fluorescence lifetime (FLT) compared to Cy3 (τ ~ 0.3 ns [3]) and Alexa 555 (τ ~ 0.3 ns [2]) in PBS.

Spectral Data

Absorption and emission spectrum of SeTau-500-NHS (K9-3162) in 5% DMF in PBS (pH 7.4)
Absorption and emission spectrum of SeTau-500-IgG conjugate (K9-3162) in PBS (pH 7.4) (Dye-to-protein ratio 1.0)

 

Fluorescence quantum yield vs. dye-to-protein ratio of SeTau-500-IgG (K9-3162) in PBS (pH 7.4) as compared to Alexa 488 — IgG conjugate
Total brightness (QY × ε × D/P) vs. dye-to-protein ratio (D/P) of SeTau-500 — IgG conjugates (K9-3162) in PBS (pH 7.4) as compared to Alexa 488 — IgG conjugate and Cy3 — IgG conjugate

 

Stability towards oxidation. Decrease in the long-wavelength absorption band of SeTau-500 (K9-3162) compared with Cy3 and fluorescein (FITC) in 1.5% hydrogen peroxide (H2O2) in PBS (pH 7.4) at 20 °C

 

References

  1. Cooper M, Ebner A, Briggs M, Burrows M, Gardner N, Richardson R, West R (2004) Cy3B™: improving the performance of cyanine dyes. J Fluoresc 14:145–150. https://doi.org/10.1023/b:jofl.0000016286.62641.59
  2. https://www.thermofisher.com/il/en/home/references/molecular-probes-the-handbook/tables/fluorescence-quantum-yields-and-lifetimes-for-alexa-fluor-dyes.html
  3. https://josephgroup.ucsd.edu/Protocols/Lifetime%20Data%20of%20Selected%20Fluorophores.pdf