Shop All Amine-Reactive Fluorophores, Biotins, Quantum Dots, & Other Labels

DyLight™ 350 NHS Ester (Thermo Scientific™)

Thermo Scientific DyLight 350 Amine-Reactive Dye is an NHS ester-activated derivative of high-performance DyLight 350 used to fluorescently label antibodies and other proteins that are then used as molecular probes for cellular imaging and other fluorescence detection methods.

DyLight 350 is a derivative of aminomethylcoumarine acetate (AMCA) and has a higher fluorescence intensity than Alexa Fluor™ 350 and AMCA in many applications. The high water solubility of DyLight Fluors means that a high dye-to-protein ratio can be attained without causing precipitation of the conjugates. DyLight 350 Amine-Reactive Dye is also available as part of two antibody labeling kit sizes.

Features of DyLight 350 NHS Ester:

High performance—DyLight 350 shows brighter fluorescence than Alexa Fluor 350 and AMCA
Specific—NHS ester-activated dye labels proteins and other molecules at primary amines (-NH2)
Optimized procedure—following the standard protocol results in antibodies with excellent dye:protein ratios and recovery rates for optimum activity and fluorescence labeling

Applications
• Primary antibody labeling for immunofluorescence microscopy, immunohistochemistry (IHC), Western blotting or ELISA assay
• Target protein labeling for in vitro and in vivo fluorescent detection strategies

DyLight 350 Amine-Reactive Dye is activated with an N-hydroxysuccinimide (NHS) ester moiety to react with exposed N-terminal α-amino groups or the ε-amino groups of lysine residues to form stable amide bonds. Learn more about NHS ester chemistry.

Typical labeling reactions require DyLight 350 Amine-Reactive Dye to first be dissolved in anhydrous dimethyl formamide (DMF) or another suitable organic solvent before adding a specific molar amount of dye to an amine-free buffer containing the protein to be labeled. However, the high solubility of DyLight Fluors permits protein solutions to be added directly to specific amounts of the labeling reagent. This feature allows DyLight 350 Amine-Reactive Dye to be provided in multiple formats with flexible protocols to achieve efficient degrees of labeling.

We also offer Standard and Microscale DyLight 350 Antibody Labeling Kits for fast and efficient fluorescent labeling of antibodies for use in fluorescence methods.The standard size kit contains all necessary components to perform three separate labeling reactions using 1 mg of IgG or similar quantities of other proteins. The microscale kit contains all of the necessary components to perform five separate labeling reactions using 100 µg of IgG. Both kit sizes include the Amine-Reactive DyLight 350 NHS-ester in convenient single-use vials as well as purification resin and spin columns for the preparation of ready-to-use conjugate.

Related Products
DyLight™ 350 Antibody Labeling Kit
DyLight™ 350 Microscale Antibody Labeling Kit

DNP-X, SE, 6-(2,4-Dinitrophenyl)aminohexanoic Acid, Succinimidyl Ester (Invitrogen™)

The amine-reactive DNP-X succinimidyl ester can be used bioconjugates that can be detected with anti-dinitrophenyl (anti-DNP) antibodies. This reactive hapten contains an additional seven-atom aminohexanoyl spacer ("X") between the fluorophore and the succinimidyl ester group. This spacer helps to separate increase accessibility to anti-DNP antibodies.

Qdot™ 655 ITK™ Amino (PEG) Quantum Dots (Invitrogen™)

Qdot® 655 ITK™ amino (PEG) quantum dots are the ideal starting material for preparing custom conjugates of ultrabright and photostable fluorescently labeled proteins or other biopolymers. These probes are functionalized with amine-derivatized PEG, which prevents non-specific interactions and provides a convenient handle for conjugation. The amino quantum dots react efficiently with isothiocyanates and succinimidyl esters, or with native carboxylic acids using water-soluble carbodiimides such as EDC. Such derivatives may be used for various labeling and tracking applications that require ultrabright and stable fluorescence. Our Qdot® ITK™ amino quantum dots are provided as 8 µM solutions and are available in 8 colors of Qdot® probes.

Important Features of Qdot® ITK™ Amino Quantum Dots:
• Qdot® 655 ITK™ amino quantum dot has emission maxima of ~655 nm
• Extremely photostable and bright fluorescence
• Efficiently excited with single-line excitation sources
• Narrow emission, large stokes shift
• Available in multiple colors
• Ideal for various labeling and tracking applications


Properties of Qdot® Nanocrystals
Qdot® probes are ideal for imaging and labeling applications that require bright fluorescent signals and/or real-time tracking. Unique among fluorescent reagents, all nine available colors of Qdot® probes can be simultaneously excited with a single (UV to blue-green) light source. This property makes these reagents excellent for economical and user-friendly multiplexing applications. Qdot® labels are based on semiconductor nanotechnology and are similar in scale to moderately sized proteins.

About the Innovator’s Tool Kit Qdot® ITK™ Reagents
These Qdot® ITK™ probes are ideal for researchers who wish to prepare specific (non-stocked) conjugates for their applications and need customizable conjugation functionality.

Other Forms of Qdot® Nanocrystals are Available
In addition to the amine-derivatized form, we offer Qdot® ITK™ quantum dots with carboxyl and aliphatic hydrocarbon modifications. We’ve also developed a wide range of Qdot® nanocrystals conjugates and labeling kits. Investigate the properties of Qdot® nanocrystals or read the Molecular Probes® Handbook Section 6.6—Qdot® Nanocrystals to find out more.

For Research Use Only. Not intended for any animal or human therapeutic or diagnostic use.

Qdot™ 565 ITK™ Amino (PEG) Quantum Dots (Invitrogen™)

Qdot® 565 ITK™ amino (PEG) quantum dots are the ideal starting material for preparing custom conjugates of ultrabright and photostable fluorescently labeled proteins or other biopolymers. These probes are functionalized with amine-derivatized PEG, which prevents non-specific interactions and provides a convenient handle for conjugation. The amino quantum dots react efficiently with isothiocyanates and succinimidyl esters, or with native carboxylic acids using water-soluble carbodiimides such as EDC. Such derivatives may be used for various labeling and tracking applications that require ultrabright and stable fluorescence. Our Qdot® ITK™ amino quantum dots are provided as 8 µM solutions and are available in 8 colors of Qdot® probes.

Important Features of Qdot® ITK™ Amino Quantum Dots:
• Qdot® 565 ITK™ amino quantum dot has emission maxima of ~565 nm
• Extremely photostable and bright fluorescence
• Efficiently excited with single-line excitation sources
• Narrow emission, large stokes shift
• Available in multiple colors
• Ideal for various labeling and tracking applications


Properties of Qdot® Nanocrystals
Qdot® probes are ideal for imaging and labeling applications that require bright fluorescent signals and/or real-time tracking. Unique among fluorescent reagents, all nine available colors of Qdot® probes can be simultaneously excited with a single (UV to blue-green) light source. This property makes these reagents excellent for economical and user-friendly multiplexing applications. Qdot® labels are based on semiconductor nanotechnology and are similar in scale to moderately sized proteins.

About the Innovator’s Tool Kit Qdot® ITK™ Reagents
These Qdot® ITK™ probes are ideal for researchers who wish to prepare specific (non-stocked) conjugates for their applications and need customizable conjugation functionality.

Other Forms of Qdot® Nanocrystals are Available
In addition to the amine-derivatized form, we offer Qdot® ITK™ quantum dots with carboxyl and aliphatic hydrocarbon modifications. We’ve also developed a wide range of Qdot® nanocrystals conjugates and labeling kits. Investigate the properties of Qdot® nanocrystals or read the Molecular Probes® Handbook Section 6.6—Qdot® Nanocrystals to find out more.

For Research Use Only. Not intended for any animal or human therapeutic or diagnostic use.

Click-iT™ SDP Ester sDIBO Alkyne for Antibody Labeling (Invitrogen™)

The Click-iT SDB Ester sDIBO Alkyne for Antibody Labeling is optimized for easy attachment to azido modified antibodies using copper-free Click chemistry. This sDIBO label can be used with antibodies that have been modified using the SiteClick Antibody Azido Modification Kit or antibodies that have been engineered to contain azido moieties. These sDIBO alkynes are improved versions of our original DIBO cyclooctynes, yielding conjugates that are less "sticky" and give lower signal background in biological samples.

This modular labeling system gives you the option to choose different fluorescent labels for your antibody and attach another molecule via streptavadin or your own molecule via amine-reactive or amine-containing moieties depending on your assay.

There are multiple Click-iT sDIBO labels to choose from:
Click-iT Alexa Fluor 488 sDIBO Alkyne for Antibody Labeling
Click-iT Alexa Fluor 555 sDIBO Alkyne for Antibody Labeling
Click-iT Alexa Fluor 647 sDIBO Alkyne for Antibody Labeling
Click-iT Biotin sDIBO Alkyne for Antibody Labeling
Click-iT Amine sDIBO Alkyne for Antibody Labeling
Click-iT SDP Ester sDIBO Alkyne for Antibody Labeling

Learn more about SiteClick labeling technology ›

Custom SiteClick Antibody Labeling Service and sDIBO labels
If you have an antibody that is considered "difficult to label" or has lost activity after labeling using a conventional method, please contact our custom service representatives to determine whether the SiteClick Antibody Labeling Service would be right for your antibody. We offer complete custom SiteClick antibody labeling services with the option of multiple detection molecules including biotin, Alexa Fluor dyes, Qdot fluorophores, R-PE, chelates for PET imaging, and many others.

Azido, PEO (4 propionic Acid, Succinimidyl Ester (3-(Azidotetra(Ethyleneoxy))Propionic Acid, Succinimidyl Ester)) (Invitrogen™)

Conjugates prepared with the amine-reactive alkyne, succinimidyl ester can be detected with an azide-containing molecule in a click chemistry reaction. Click chemistry describes a class of chemical reactions that use bio-orthogonal or biologically unique moities to label and detect a molecule of interest using a two-step procedure. The two-step reaction procedure involves a copper-catalyzed triazole formation of an azide and an alkyne. Click reactions have several characteristics: the reaction between the detection moieties is efficient; no extreme temperatures or solvents are required; the reaction product is stable; the components of the reaction are bioinert; and perhaps most importantly, no side reactions occur – the label and detection tags react selectively and specifically with one another. Unlike traditional chemical reactions utilizing succinimidyl esters or maleimides that target amines and sulfhydryls – functional groups that are not unique – click chemistry-labeled molecules can be applied to complex biological samples and be detected with unprecedented sensitivity due to extremely low background.

DyLight™ 755 NHS Ester (Thermo Scientific™)

Thermo Scientific DyLight 755 Amine-Reactive Dye is an NHS ester-activated derivative of high-performance DyLight 755 used to fluorescently label antibodies and other proteins that are then used as molecular probes for cellular imaging and other fluorescence detection methods.

DyLight 755 is a near-IR fluor that is invisible to the naked eye but increases the staining options when using infrared imaging systems. DyLight 755 has spectral properties that are very similar to other near-IR dyes, including Alexa Fluor™ 750. The high water solubility of DyLight Fluors means that a high dye-to-protein ratio can be attained without causing precipitation of the conjugates. DyLight 755 Amine-Reactive Dye is also available as part of two antibody labeling kit sizes.

Features of DyLight 755 NHS Ester:

High performance—DyLight 755 replaces Alexa Fluor 755 for near-infrared staining
Specific—NHS ester-activated dye labels proteins and other molecules at primary amines (-NH2)
Optimized procedure—following the standard protocol results in antibodies with excellent dye:protein ratios and recovery rates for optimum activity and fluorescence labeling

Applications:
• Primary antibody labeling for immunofluorescence microscopy, immunohistochemistry (IHC), Western blotting or ELISA assay
• Target protein labeling for in vitro and in vivo fluorescent detection strategies

DyLight 755 Amine-Reactive Dye is activated with an N-hydroxysuccinimide (NHS) ester moiety to react with exposed N-terminal α-amino groups or the ε-amino groups of lysine residues to form stable amide bonds. Learn more about NHS ester chemistry.

Typical labeling reactions require the dye to first be dissolved in anhydrous dimethyl formamide (DMF) or another suitable organic solvent before adding a specific molar amount of dye to an amine-free buffer containing the protein to be labeled. However, the high solubility of DyLight Fluors permits protein solutions to be added directly to specific amounts of the labeling reagent. This feature allows DyLight 755 Amine-Reactive Dye to be provided in multiple formats with flexible protocols to achieve efficient degrees of labeling.

We also offer Standard and Microscale DyLight 755 Antibody Labeling Kits for fast and efficient fluorescent labeling of antibodies for use in fluorescence methods.The standard size kit contains all necessary components to perform three separate labeling reactions using 1 mg of IgG or similar quantities of other proteins. The microscale kit contains all of the necessary components to perform five separate labeling reactions using 100 µg of IgG. Both kit sizes include the Amine-Reactive DyLight 755 NHS-ester in convenient single-use vials as well as purification resin and spin columns for the preparation of ready-to-use conjugate.

Related Products
DyLight™ 755 Antibody Labeling Kit
DyLight™ 755 Microscale Antibody Labeling Kit

Texas Red™-X, Succinimidyl Ester, single isomer (Invitrogen™)

The amine-reactive Texas Red®-X, succinimidyl ester can be used to can be used to create bright red-fluorescent bioconjugates with excitation/emission maxima ~595/615 nm. This reactive dye contains an additional seven-atom aminohexanoyl spacer ("X") between the fluorophore and the succinimidyl ester group. This spacer helps to separate the fluorophore from its point of attachment, potentially reducing the interaction of the fluorophore with the biomolecule to which it is conjugated.

DyLight™ 650-4xPEG NHS Ester (Thermo Scientific™)

Thermo Scientific DyLight 650-4xPEG Amine-Reactive Dye is a derivative of our high-performance DyLight 650 Dye that can be used to fluorescently label antibodies and other proteins for far-red detection.

The DyLight 650-4xPEG dye contains 4 polyethylene glycol (PEG) chains that are non-cytotoxic, enhance fluorescence, and reduce nonspecific binding of conjugates made with them. Conjugates made with DyLight 650-4xPEG Dye can be used as molecular probes for cellular imaging and other fluorescence detection methods. The far-red to NIR fluorescence properties of DyLight 650-4xPEG Dye make it especially useful in a variety of biological, chemical, and pharmaceutical applications, including in vivo imaging. The PEG chains also improve solubility of the dyes and labeled molecules in aqueous solution, aid in cell permeability, and improve tissue retention.

Features of DyLight 650-4xPEG NHS Ester:

High fluorescence intensity—significantly brighter fluorescence than Alexa Fluor™ 647
PEGylated—improves solubility in aqueous solution and aids in cell permeability

Applications:
• Fluorescence microscopy
In vivo or ex vivo imaging
• Cell-based assays
• Flow cytometry/fluorescence-activated cell sorting (FACS)

DyLight 650-4xPEG Amine-Reactive Dye is activated with an N-hydroxysuccinimide (NHS) ester moiety to react with exposed N-terminal α-amino groups or the ε-amino groups of lysine residues to form stable amide bonds. Learn more about NHS ester chemistry.

Typical labeling reactions require the dye to first be dissolved in anhydrous dimethyl formamide (DMF) or another suitable organic solvent before adding a specific molar amount of dye to an amine-free buffer containing the protein to be labeled. However, the high solubility of DyLight Fluors permits protein solutions to be added directly to the labeling reagent.

6-TAMRA, SE (6-Carboxytetramethylrhodamine, Succinimidyl Ester), single isomer (Invitrogen™)

The isomeric 6-TAMRA, SE is an amine-reactive form of tetramethylrhodamine. The single-isomer preparations of TAMRA are most important for high-resolution techniques such as DNA sequencing and capillary electrophoresis. 6-TAMRA is one of the traditional fluorophores used for automated DNA sequencing.

DyLight™ 554-R1 NHS Ester (Thermo Scientific™)

DyLight 554-R1 provides bright fluorescent detection for imaging. This rhodamine-based dye has excitation and emission peaks at 548 and 574 nm, respectively (in ethanol), and an extinction coefficient of 100,000 M-1cm-1. The amine-reactive DyLight 554-R1 NHS Ester allows for simple modification of antibodies, proteins, peptides, and other biomolecules through amide bond formation.

General features of DyLight yellow-emitting specialty dyes:

NHS ester reactive group—allows immediate labeling of antibodies, proteins, peptides and other amine-containing molecules through amide bond formation
Multiple solubility options—choose from hydrophilic to hydrophobic dyes to optimize the right dye label for the best performance in a given application

Dyes can be selected based upon their characteristic excitation and emission properties or relative hydrophilicity and hydrophobicity attributes. Dyes that contain a greater number of negatively charged sulfonates generally will have greater water solubility than dyes with fewer sulfonates. More hydrophobic dyes often provide better cell penetrating ability in vivo, while more hydrophilic dyes have less nonspecific binding potential.

Criteria to consider when choosing a DyLight Yellow-emitting Specialty Dye
• Excitation and emission wavelengths—choose the best dye to match the excitation and emission capabilities of your instrument
• Water solubility—choose a dye based on its relative hydrophilicity, which directly correlates to the number of negatively-charged sulfonates it has on its core structure. More hydrophilic dyes are best at maintaining water solubility of a labeled antibody and limiting the nonspecific binding of the conjugate. More hydrophobic dyes often are best at penetrating tissues and cell membranes in vivo, meaning that dyes with fewer sulfonates may work best for some applications.

Applications:
• Fluorescence imaging
• Fluorescence correlation spectroscopy
• Flow cytometry
• Imaging
• Antibody labeling
• Direct immunofluorescence staining
• ELISA
• Western blotting
• Protein microarrays
• Polymer labeling
• Peptide labeling
• Phalloidin labeling for actin staining

Related Products
DyLight™ 554-R0 NHS Ester

ATTO-TAG™ FQ Amine-Derivatization Kit (Invitrogen™)

ATTO-TAG™ FQ (3-2-(furoyl quinoline-2-carboxaldehyde) included in this amine-derivatization kit reacts specifically with primary amines to form conjugates that can be analyzed by electrophoretic or chromatographic methods. The resulting products of FQ are maximally excited at 480 nm or by the 488 nm spectral line of the argon-ion laser and have emission maxima at ~590 nm. The high sensitivity, freedom from background and long-wavelength excitability make these potential reagents for researcher, diagnostic and forensic applications.

5-CR 6G, SE (5-Carboxyrhodamine 6G, Succinimidyl Ester), single isomer (Invitrogen™)

The amine-reactive form of 5-CR 6G is used for oligonucleotide labeling and automated DNA sequencing applications. Conjugates of this dye have longer-wavelength spectra than the spectra of Lisaamine™ rhodamine B conjugates, but somewhat shorter-wavelength spectra than those of Texas Red® conjugates.

pHrodo™ Green STP Ester (Invitrogen™)

The amine-reactive pH-sensitive pHrodo® Green STP ester dye is suitable for the creation of bioconjugates to study endocytosis and phagocytosis. pHrodo® Green dramatically increases fluorescence as the pH of its surroundings become more acidic.
• Use pH-sensitive pHrodo® Green STP ester to make pH-sensitive bioconjugates of your choice
• Get faster, more accurate results than with any other endocytosis or phagocytosis assay—no need for wash steps or quenchers
• Multiplex with red fluorescent markers such as RFP, pHrodo® Red, and many others

The increase in fluorescence of pHrodo® Green as pH changes from basic to acidic correlates with the acidification of intracellular vesicles, making it an ideal tool to study endocytosis or phagocytosis and their regulation by environmental factors, drugs, or pathogens. The spectral properties of pHrodo® Green makes it useful for multi-color experiments. pHrodo® Green can be detected using most standard green fluorescent filter sets and has been validated for use on a variety of platforms, including flow cytometry, fluorescent microscopy, and high content screening (HCS). The lack of fluorescence of pHrodo® Green in a typical extracellular environment eliminates the need for wash steps or quencher dyes in the experimental workflow.

The pHrodo® Green STP ester is an amine reactive dye that can be used to make pHrodo® Green bioconjugates in aqueous buffer. The STP ester will react with primary amines on a protein, cell, or virus to create a stable conjugate that can be used in live cell assays or stored for later use.

Amine reactive pHrodo® dye is also available with red fluorescence (see pHrodo® Red SE). In addition, thiol-reactive pHrodo® Red Maleimide and Green Maleimide are a great alternative to amine-reactive dyes for antibody labeling. Thiol labeling ensures that the dye will not attach to the binding region of the antibody. pHrodo® Green and Red conjugates, for example dextran, E. coli and S. aureus, are also available in ready-to-use form.

For Research Use Only. Not for human or animal therapeutic or diagnostic use.

EZ-Link™ Sulfo NHS-LC-LC-Biotin, No-Weigh™ Format (Thermo Scientific™)

Thermo Scientific EZ-Link Sulfo-NHS-LC-LC-Biotin enables simple and efficient biotin labeling of antibodies, proteins, and any other primary amine–containing macromolecules. Specific labeling of cell surface proteins is another common application for these uniquely water-soluble and membrane impermeable reagents.

Thermo Scientific No-Weigh products are specialty reagents provided in a pre-aliquoted format. The pre-weighed packaging prevents the loss of reagent reactivity and contamination over time by eliminating the repetitive opening and closing of the vial. The format enables use of a fresh vial of reagent each time, eliminating the hassle of weighing small amounts of reagents and reducing concerns over reagent stability.

Features of EZ-Link Sulfo-NHS-LC-LC-Biotin:

Protein labeling—biotinylate antibodies to facilitate immobilization, purification or detection using streptavidin resins or probes
Cell surface labeling—biotinylates only surface proteins of whole cells because the negatively charged reagent does not permeate cell membranes
Amine-reactive—reacts with primary amines (-NH2), such as the side-chain of lysines (K) or the amino-termini of polypeptides
Soluble—charged sulfo-NHS group increases reagent water solubility compared to ordinary NHS-ester compounds
Irreversible—forms permanent amide bonds; spacer arm cannot be cleaved
Doubly long —spacer arm (total length added to target) is 22.4 angstroms; this extended arm helps to minimize steric hindrance for biotin binding

Sulfo-NHS-LC-LC-Biotin is the longest of three very similar EZ-Link Reagents that are water-soluble, non-cleavable, and enable simple and efficient biotinylation of antibodies, proteins and any other primary amine-containing macromolecules in solution. Specific labeling of cell surface proteins is another common application for these uniquely water-soluble and membrane impermeable reagents. Differing only in their spacer arm lengths, the three Sulfo-NHS-ester reagents offer the possibility of optimizing labeling and detection experiments where steric hindrance of biotin binding is an important factor.

We manufacture biotin reagents to ensure the highest possible overall product integrity, consistency, and performance for the intended research applications.

N-Hydroxysulfosuccinimide (NHS) esters of biotin are the most popular type of biotinylation reagent. NHS-activated biotins react efficiently with primary amino groups (-NH2) in alkaline buffers to form stable amide bonds. Proteins (e.g., antibodies) typically have several primary amines that are available as targets for labeling, including the side chain of lysine (K) residues and the N-terminus of each polypeptide.

Varieties of biotin NHS-ester reagents differ in length, solubility, cell permeability and cleavability. Non-sulfonated NHS-biotins are cell permeable but must be dissolved in organic solvent such as DMSO or DMF. Sulfo-NHS biotins (and those with pegylated spacers) are directly water soluble but not membrane permeable. Varieties containing disulfide bonds can be cleaved using reducing agents, enabling the biotin group to be disconnected from the labeled protein.