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Tide Fluor™ Dyes, Optimized FRET Donors

Although EDANS, FAM, TAMRA, ROX, Cy3® and Cy5® have been widely used to develop a variety of FRET peptide and FRET oligonucleotide probes, there are still some limitations in the use of these dyes. For example, the weak absorption and environment sensitive fluorescence of EDANS have severely limited its sensitivity for developing protease assays and nucleic acid detection probes. Compared to EDANS, fluorescein-based probes (such as FAM, HEX, JOE and TET) have stronger absorption and fluorescence. However the fluorescence of fluorescein-based probes is strongly dependent on pH. They only exhibit the strongest fluorescence at higher pH. This pH dependence makes the fluorescein-based fluorescent probes inconvenient for the assays that require low pH. In addition, most of fluorescein-based probes have quite low photostability, which limits their applications in fluorescence imaging.

Among cyanine dyes, non-sulfonated Cy3® and Cy5® are widely used for developing a variety of peptide and oligonucleotide probes, but they have quite low fluorescence quantum yields in aqueous media. The sulfonated Cy3® and Cy5® have improved fluorescence quantum yields than those of non-sulfonate cyanines. Alexa Fluor™ dyes have improved performance, but are extremely expensive, thus are unpractical for preparing peptide and oligonucleotide conjugates in some cases.

To address these limitations, AAT Bioquest has developed Tide Fluor™ donor dyes that are optimized as building blocks for developing FRET peptides and FRET oligonucleotides for a variety of biological applications. Our Tide Fluor™ dyes (such as TF1, TF2, TF3, TF4, TF5, TF6, TF7 and TF8) have strong fluorescence and good photostability. TF2 dyes have the similar excitation and emission wavelengths to those of carboxyfluoresceins (FAM), making them readily used for the biological applications done with fluoresceins. TF2 dyes have much stronger fluorescence at physiological conditions and they are much more photostable than FAM probes. Compared to other fluorescent dyes alternative to fluoresceins and Cy dyes (such as Alexa Fluor® and DyLight™ dyes), Tide Fluor™ dyes are much more cost-effective with comparable or even better performance for your desired biological applications. Tide Fluor™ dyes have almost identical spectral properties to Alexa Fluor® dyes as discussed below. However, on oligonucleotides and peptides, TF3 dyes are much brighter and more photostable than Cy3®, Alexa Fluor® 555 and DyLight™ 555. We recommend you try our Tide Fluor™ dyes that are optimized for labeling oligonucleotides and peptides at much lower cost with comparable performance to Alexa Fluor® dyes.

The normalized fluorescence spectra of Tide Fluor™ dyes.

Key Features of Tide Fluor™ Dyes

  • Optimized to pair with Tide Quencher™ dark acceptors
  • Stronger fluorescence intensity to enhance assay sensitivity
  • pH-insensitive and environment-insensitive fluorescence
  • Higher photostability to improve fluorescence imaging
  • Adjustable water solubility
  • A variety of reactive forms available for conjugations


Table 1. Tide Fluor™ equivalents of common dyes

If you are using
Try this Tide Fluor™ dye
EDANSTide Fluor™ 1 (TF1)
FAM, FITC, Alexa Fluor® 488Tide Fluor™ 2 (TF2)
Alexa Fluor® 488Tide Fluor™ 2WS (TF2WS)
Cy3®, Alexa Fluor® 555Tide Fluor™ 3 (TF3)
Cy3®, Alexa Fluor® 555Tide Fluor™ 3WS (TF3WS)
ROX, Texas Red®, Alexa Fluor® 594Tide Fluor™ 4 (TF4)
Cy5®, Alexa Fluor® 647Tide Fluor™ 5WS (TF5WS)
Cy5.5®, IRDye® 700, Alexa Fluor® 680Tide Fluor™ 6WS (TF6WS)
Cy7®, Alexa Fluor® 750Tide Fluor™ 7WS (TF7WS)
IRDye® 800Tide Fluor™ 8WS (TF8WS)

Table 2. Tide Fluor™ Dyes for Developing FRET Probes

Tide Fluor™ Donor
Ex (nm)
Em (nm)
Features and Benefits
Ordering Information
Tide Fluor™ 1 (TF1)345442
  • Alternative to EDANS
  • Much stronger absorption
  • Much stronger fluorescence
  • Less environmental sensitivity
Cat# 2236 (TF1 azide, click chemistry)
Cat# 2237 (TF1 alkyne, click chemistry)
Cat# 2238 (TF1 acid)
Cat# 2239 (TF1 amine)
Cat# 2242 (TF1 maleimide, SH-reactive)
Cat# 2244 (TF1 SE, NH2-reactive)
Tide Fluor™ 2 (TF2)500527
  • Alternative to FAM, FITC and Alexa Fluor® 488
  • pH-insensitive fluorescence
  • Good photostability
Cat# 2245 (TF1 acid)
Cat# 2246 (TF2 amine)
Cat# 2247 (TF2 maleimide SH-reactive)
Cat# 2248 (TF2 SE, NH2-reactive)
Cat# 2252 (TF2 azide, click chemistry)
Cat# 2253 (TF2 alkyne, click chemistry)
Tide Fluor™ 3 (TF3)555584
  • Alternative to Cy3® and Alexa Fluor® 555
  • Strong fluorescence
  • Good photostability
Cat# 2254 (TF3 azide, click chemistry)
Cat# 2255 (TF3 alkyne, click chemistry)
Cat# 2268 (TF3 acid)
Cat# 2269 (TF3 amine)
Cat# 2270 (TF3 maleimide, SH-reactive)
Cat# 2271 (TF3 SE, NH2-reactive)
Tide Fluor™ 3WS (TF3WS)555565
  • Alternative to Cy3® and Alexa Fluor® 555
  • Strong fluorescence
  • Good photostability
Cat# 2345 (TF3WS acid)
Cat# 2346 (TF3WS SE, NH2-reactive)
Tide Fluor™ 4 (TF4)590618
  • Alternative to ROX, Texas Red® and Alexa Fluor® 594
  • Strong fluorescence
  • Good photostability
Cat# 2285 (TF4 acid)
Cat# 2286 (TF4 amine)
Cat# 2287 (TF4 maleimide, SH-reactive)
Cat# 2289 (TF4 SE, NH2-reactive)
Cat# 2300 (TF4 azide, click chemistry)
Cat# 2301 (TF4 alkyne, click chemistry)
Tide Fluor™ 5WS (TF5WS)649664
  • Alternative to Cy5® and Alexa Fluor® 647
  • Strong fluorescence
  • Good photostability
Cat# 2275 (TF5WS azide, click chemistry)
Cat# 2276 (TF5WS alkyne, click chemistry)
Cat# 2278 (TF5WS, acid)
Cat# 2279 (TF5WS amine)
Cat# 2280 (TF5WS maleimide, SH-reactive)
Cat# 2281 (TF5WS SE, NH2-reactive)
Tide Fluor™ 6WS (TF6WS)676695
  • Alternative to Cy5.5®, IRDye® 700 and Alexa Fluor® 680
  • Strong fluorescence
  • Good photostability
Cat# 2291 (TF6WS acid)
Cat# 2292 (TF6WS amine)
Cat# 2293 (TF6WS maleimide, SH-reactive)
Cat# 2294 (TF6WS SE, NH2-reactive)
Cat# 2302 (TF6WS azide, click chemistry)
Cat# 2303 (TF6WS alkyne, click chemistry)
Tide Fluor™ 7WS (TF7WS)749775
  • Alternative to Cy7® and Alexa Fluor® 750
  • Strong fluorescence
  • Good photostability
Cat# 2304 (TF7WS azide, click chemistry)
Cat# 2305 (TF7WS alkyne, click chemistry)
Cat# 2330 (TF7WS acid)
Cat# 2331 (TF7WS amine)
Cat# 2332 (TF7WS maleimide, SH-reactive)
Cat# 2333 (TF7WS SE, NH2-reactive)
Tide Fluor™ 8WS (TF8WS)775807
  • Alternative to IRDye® 800
  • Strong fluorescence
  • Good photostability
Cat# 2306 (TF8WS azide, click chemistry)
Cat# 2307 (TF8WS alkyne, click chemistry)
Cat# 2335 (TF8WS acid)
Cat# 2336 (TF8WS amine)
Cat# 2337 (TF8WS maleimide, SH-reactive)
Cat# 2338 (TF8WS SE, NH2-reactive)