Name: Cy3B PEG12 NHS ester
Brand: AAT Bioquest
SKU: 939
Price: 148 USD
Availability: InStock

Cy3B PEG12 NHS ester

Cy3B PEG12 NHS ester is an enhanced cyanine dye with superior photostability and a long PEG12 spacer that reduces aggregation and improves bioconjugation efficiency for protein and antibody labeling in demanding imaging applications.

Amine-Reactive NHS ester: Efficiently conjugates to primary amines on proteins, peptides, and other biomolecules
Cy3B Fluorophore: Superior brightness and photostability compared to traditional Cy3 dyes
PEG12 Spacer: Enhances water solubility and reduces nonspecific binding and steric hindrance
Ideal for High-Sensitivity Applications: Performs well in demanding fluorescence microscopy, flow cytometry, FISH, and single-molecule imaging experiments

The chemical structure of Cy3B PEG12 NHS ester.

Datasheet

SDS

Catalog	Size	Price	Quantity
939	1 mg	Price

Overview

Cy3B PEG12 NHS ester is a bright, amine-reactive fluorescent labeling reagent that combines the superior photostability of the Cy3B fluorophore with the enhanced solubility and reduced steric hindrance of a PEG12 spacer. This compound features an N-hydroxysuccinimide (NHS) ester functional group, which reacts efficiently with primary amines on proteins, peptides, and other biomolecules under mild conditions. The inclusion of a PEG12 linker improves hydrophilicity and minimizes nonspecific interactions, making it especially suitable for applications that require high labeling specificity and minimal background signal. Cy3B is known for its high quantum yield and resistance to photobleaching, offering significant advantages over traditional Cy3 dyes in demanding applications such as fluorescence microscopy, flow cytometry, and single-molecule detection. With excitation and emission maxima around 560 nm and 571 nm, respectively, Cy3B PEG12 NHS ester is compatible with standard Cy3 filter sets and serves as a reliable choice for the development of robust, high-performance fluorescent probes.

Calculators

Common stock solution preparation

Table 1. Volume of DMSO needed to reconstitute specific mass of Cy3B PEG12 NHS ester to given concentration. Note that volume is only for preparing stock solution. Refer to sample experimental protocol for appropriate experimental/physiological buffers.

	0.1 mg	0.5 mg	1 mg	5 mg	10 mg
1 mM	79.526 µL	397.63 µL	795.26 µL	3.976 mL	7.953 mL
5 mM	15.905 µL	79.526 µL	159.052 µL	795.26 µL	1.591 mL
10 mM	7.953 µL	39.763 µL	79.526 µL	397.63 µL	795.26 µL

Molarity calculator

Enter any two values (mass, volume, concentration) to calculate the third.

Mass (Calculate)		Molecular weight		Volume (Calculate)		Concentration (Calculate)		Moles
mg	÷	1257.45 g/mol	=	mL	x	mM	=	mmol

References

View all 44 references: Citation Explorer

In silico screening of photostabilizing reagents for cyanine-based single molecule fluorescence.

Authors:

Ramos-Sanchez, Jorge E and Gidi, Yasser and Lovell, Terri C and Payne, Liam and Sakaya, Aya and Cosa, Gonzalo

Journal:

Physical chemistry chemical physics : PCCP (2025): 9227-9234

The Effect of Conjugated Nitrile Structures as Acceptor Moieties on the Photovoltaic Properties of Dye-Sensitized Solar Cells: DFT and TD-DFT Investigation.

Authors:

Tommalieh, Maha J and Aljameel, Abdulaziz I and Hussein, Rageh K and Al-Heuseen, Khalled and Alghamdi, Suzan K and Alrub, Sharif Abu

Journal:

International journal of molecular sciences (2024)

Illuminating Neuropeptide Y Y4 Receptor Binding: Fluorescent Cyclic Peptides with Subnanomolar Binding Affinity as Novel Molecular Tools.

Authors:

Gleixner, Jakob and Kopanchuk, Sergei and Grätz, Lukas and Tahk, Maris-Johanna and Laasfeld, Tõnis and Veikšina, Santa and Höring, Carina and Gattor, Albert O and Humphrys, Laura J and Müller, Christoph and Archipowa, Nataliya and Köckenberger, Johannes and Heinrich, Markus R and Kutta, Roger Jan and Rinken, Ago and Keller, Max

Journal:

ACS pharmacology & translational science (2024): 1142-1168

Fluorescence based HTS-compatible ligand binding assays for dopamine D3 receptors in baculovirus preparations and live cells.

Authors:

Tahk, Maris-Johanna and Laasfeld, Tõnis and Meriste, Elo and Brea, Jose and Loza, Maria Isabel and Majellaro, Maria and Contino, Marialessandra and Sotelo, Eddy and Rinken, Ago

Journal:

Frontiers in molecular biosciences (2023): 1119157

Characterization of Fluorescent Dyes Frequently Used for Bioimaging: Photophysics and Photocatalytical Reactions with Proteins.

Authors:

Archipowa, Nataliya and Wittmann, Lukas and Köckenberger, Johannes and Ertl, Fabian J and Gleixner, Jakob and Keller, Max and Heinrich, Markus R and Kutta, Roger Jan

Journal:

The journal of physical chemistry. B (2023): 9532-9542

Physical properties

Molecular weight	1257.45
Solvent	DMSO

Spectral properties

Correction factor (260 nm)	0.048
Correction factor (280 nm)	0.069
Extinction coefficient (cm ^-1 M ^-1)	120000 ¹
Excitation (nm)	560
Emission (nm)	571
Quantum yield	0.58 ¹

Storage, safety and handling

H-phrase	H303, H313, H333
Hazard symbol	XN
Intended use	Research Use Only (RUO)
R-phrase	R20, R21, R22
Storage	Freeze (< -15 °C); Minimize light exposure

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Page updated on January 8, 2026