The published discovery in 2004 of SPAAC, also known as “”copper free click chemistry,”” by Carolyn Bertozzi and coworkers improved the click chemistry toolbox. Toxic copper catalysts were eliminated, making the reaction truly bioorthogonal. By removing the copper(I) catalyst from the reaction, living cells can be labeled with reagents designed for SPAAC. Since the original publication, multiple improvements in strained cyclooctyne reagents resulted in the development of DBCO as a nearly perfect azide partner for SPAAC.

To use DBCO-TFP ester in aqueous media or in cells, it should be conjugated to a water-soluble dPEG® product. Vector Laboratories offers numerous products for this purpose, including amino alcohols and amino acids. We also offer many ready-to-use DBCO-functionalized dPEG® products.

Specifications

The post DBCO-TFP ester appeared first on VectorLabs.

Fluorescein and its derivatives are among the most popular dyes in use today for labeling proteins and cells. Unfortunately, these dyes are hydrophobic, and care must be taken to avoid over-labeling because over-labeling can result in quenching and possibly aggregation and precipitation of the conjugates through non-specific hydrophobic interactions.

DBCO is an increasingly popular choice for SPAAC chemistry, also known as ""copper-free click chemistry"" because it avoids the use of cytotoxic copper(I) ions and allows reactions to occur in and with living cells. Although DBCO may react with free sulfhydryl groups under some conditions, it is highly selective for azides. Because azides must be introduced artificially into proteins, DBCO is considered a bioorthogonal click chemistry reagent.

The introduction of a flexible dPEG® spacer between carboxyfluorescein and DBCO increases the molecule's hydrodynamic volume and imparts water solubility to DBCO-dPEG®12-carboxyfluorescein. Thus, DBCO-dPEG®12-carboxyfluorescein provides a highly selective, flexible, water-soluble way to label proteins, peptides, and cells with carboxyfluorescein using a bio-orthogonal reagent designed to simplify analysis and characterization of the conjugate.

Specifications

The post DBCO-dPEG®₁₂-carboxyfluorescein appeared first on VectorLabs.

TAMRA DBCO reacts with azides via a copper-free “click chemistry” reaction to form a stable triazole and does not require Cu-catalyst or elevated temperatures. This copper-free variation of click reaction overcomes a major shortcoming of copper-catalyzed click reaction – the need for copper catalyst. Copper can damage fluorescent proteins, Quantum Dot nanocyrstals, certain enzymes, and photoproteins like RPE. The presence of copper is also problematic in staining the surface of live cells.

[caption id="attachment_24144" align="alignnone" width="1000"] Abs/Em Spectra[/caption]

Specifications

The post TAMRA DBCO appeared first on VectorLabs.

The post IR 650 DBCO appeared first on VectorLabs.

SY-7 DBCO (QSY®-7 equivalent) is a nonfluorescent acceptor dye for preparation of peptide and oligonucleotide FRET probes. A broad and intense quenching range from 500-600 nm makes it useful as an acceptor in fluorescence resonance energy transfer (FRET) applications in conjunction with fluorescent dyes at 520 nm to 600 nm, such as Fluorescein, Oregon Green, Carboxyrhodamine 110 (Rhodamine Green), Alexa Fluor® 488, 532, 546, 555, 568, Cy3, TAMRA and ROX dyes.

SY-7 DBCO reacts with azides via a copper-free “click chemistry” reaction to form a stable triazole and does not require Cu-catalyst or elevated temperatures. In application where the presence of copper is a concern SY-7 DBCO is an ideal alternative to copper requiring fluorescent alkynes.

[caption id="attachment_27189" align="alignnone" width="1000"] Abs/Em Spectra[/caption]

Specifications

The post SY-7 DBCO appeared first on VectorLabs.

Universal Black 3 Quencher (UBQ-3, Black Hole Quencher®-3 (BHQ®-3) equivalent) is a dark, far-red nonfluorescent acceptor dye with no native emission. UBQ-3 is often used as an acceptor for preparation of fluorogenic dual-labeled probes, qPCR probes, and for other fluorescence-quenched probe applications. A broad and intense quenching range from 620-730 nm makes it useful as an acceptor in fluorescence resonance energy transfer (FRET) applications in conjunction with far-red to near-IR emitting dyes such as Cy5, Cy5.5, Alexa Fluor® 633, 647, 700, IRDye® 650, 680 and 700.
UBQ-3 is structurally identical to BHQ®-3.

UBQ-3 DBCO reacts with azides via a copper-free “click chemistry” reaction to form a stable triazole and does not require Cu-catalyst or elevated temperatures. Often a reagent of choice for labeling intact proteins, lipids and peptides where the presence of cytotoxic copper catalyst is not acceptable.

[caption id="attachment_28210" align="alignnone" width="1000"] Abs/Em Spectra[/caption]

Specifications

The post UBQ-3 DBCO appeared first on VectorLabs.

SY-21 DBCO (QSY®-21 equivalent) is a nonfluorescent acceptor dye often used for preparation of peptide and oligonucleotide FRET probes. A broad and intense quenching range from 580 nm to 680 nm makes it useful as an acceptor in fluorescence resonance energy transfer (FRET) applications in conjunction with fluorescent dyes at 580 nm to 680 nm, such as Fluorescein, Alexa Fluor® 568, 594, 633, 647, TAMRA, ROX, Texas Red and Cy5.

SY-21 DBCO reacts with azides via a copper-free “click chemistry” reaction to form a stable triazole and does not require Cu-catalyst or elevated temperatures. In application where the presence of copper is a concern SY-21 DBCO is an ideal alternative to copper requiring fluorescent alkynes.

[caption id="attachment_27198" align="alignnone" width="1000"] Abs/Em Spectra[/caption]

Specifications

The post SY-21 DBCO appeared first on VectorLabs.

SY-9 (QSY®-9 equivalent) is a more hydrophilic version of the popular SY-7 dark quencher (QSY®-7 equivalent). This nonfluorescent acceptor dye is often used for the preparation of peptide FRET probes. A broad and intense quenching range from 500-600 nm makes it useful as an acceptor in fluorescence resonance energy transfer (FRET) applications in conjunction with dyes emitting at 500 nm to 600 nm, such as Fluorescein, Oregon Green, Carboxyrhodamine 110 (Rhodamine Green), Alexa Fluor® 488, 532, 546, 555, 568, Cy3, TAMRA and ROX dyes.

SY-9 DBCO reacts with azides via a copper-free “click chemistry” reaction to form a stable triazole and does not require Cu-catalyst or elevated temperatures.

[caption id="attachment_27189" align="alignnone" width="1000"] Abs/Em Spectra[/caption]

Specifications

The post SY-9 DBCO appeared first on VectorLabs.

Cyanine heptamethine dyes are well-known NIR fluorophores, with emission wavelengths >740 nm, and often are reagents of choice for labeling antibodies. Two of the most popular commercial NIR cyanine heptamethine dyes for antibody conjugation are IRDye 800CW and DyLight 800. While these NIR dyes are undoubtedly useful for many types of immunofluorescence technologies, the resulting NIR dye-labeled antibodies sometimes exhibit performance limitations due to three inherent fluorophore concerns. (1) A meso-OAryl group connected directly to the heptamethine fluorochrome group is susceptible to nucleophilic displacement by biological amines and thiols^{1, 2} resulting in a diminished chemical stability of the dye-antibody conjugates during synthesis, storage, or the time-course of an imaging experiment. In addition, the electron-donating meso-OAryl group promotes high fluorochrome reactivity with electrophilic singlet oxygen, resulting in relatively poor dye photostability.^3,4 (2) Both dyes are flat molecules with a hydrophobic core and a polyanionic charge periphery. Thus, the chemical conversion of a small polar, cationic lysine residue on the antibody surface to a large hydrophobic, polyanionic dye derivative has the potential to produce substantial changes in antibody folding and physiochemical properties, leading to lower antibody stability and decreased target specificity.^4-8 (3) When activated versions of these hydrophobic dyes are conjugated to an antibody surface, they tend to attach at the proximal lysine sites as stacked face-to-face dimers, which produces a diagnostic H-dimer peak in the absorbance spectra that is nonfluorescent.^8,9 Moreover, the close stacking of proximal conjugated IRDye 800CW or DyLight800 on an antibody surface amplifies the potential for a deleterious effect on antibody targeting because of a localized patch of polyanionic charge and hydrophobicity.

In order to address these drawbacks of commercially NIR cyanine a conceptually new class of sterically shielded NIR dyes was developed in Dr. Bradley D. Smith laboratory.^{10, 11} These dyes contain two shielding PEG arms directly over both faces of the heptamethine fluorochrome blocking any undesired bimolecular association processes and thus enhance the fluorescence brightness. A recently published antibody labeling study clearly demonstrated 1-2 order of magnitude increase in brightness compared to commercially available NIR dyes as a result of almost complete prevention of stacking of multiple fluorophores appended to the antibody surface.^{10, 11}

These sterically shielded NIR dyes with greatly improved chemical and photochemical stability and substantially enhanced brightness will enable researchers to greatly improve various types of indirect NIR immunofluorescence imaging and diagnostics applications that require high sensitivity and also develop new photonintense techniques that require high photostability.

MB 800Z is a zwiteroinic, charge-balanced dye with an equal number of anionic sulfonate and cationic ammonium residues, a structural feature that is known to reduce interactions with off -target biological surfaces.

[caption id="attachment_27084" align="alignnone" width="1000"] Abs/Em Spectra[/caption]

Specifications

The post AZDye 800 DBCO appeared first on VectorLabs.

AZDye™ 633 DBCO is a bright and photostable far-red fluorescent probe with excitation ideally suited to the 633 nm or 635 nm laser excitation source. AZDye™ 633 DBCO is water-soluble, pH-insensitive from pH 4 to pH 10. AZDye™ 633 spectrally is almost identical to Alexa Fluor® 633, DyLight® 633 and CF® 633 Dye. Combination of superior brightness and very low autofluorescence background signal in most biological samples in far-red spectral region allows for very sensitive detection of azide-labeled biomolecules via copper-free click reaction using AZDye™ 633 DBCO.

[caption id="attachment_27033" align="alignnone" width="1000"] Abs/Em Spectra[/caption]

Specifications

The post AZDye 633 DBCO appeared first on VectorLabs.