There are two varieties of cyanine dyes: non-sulfonated cyanines, and sulfonated cyanines. For many applications they are interchangeable, because their spectral properties are nearly identical. Both sulfonated and non-sulfonated dyes can be used for the labeling of biomolecules such as DNA and proteins. The difference between the dyes is their solubility: sulfo- dyes are water-soluble, and they do not use of organic co-solvent for the labeling in aqueous environment. They are less prone to aggregation in water. There are cases when one of the type of cyanines is desired.

Available non-sulfonated dyes incude Cy3, Cy3.5, Cy5, Cy5.5, Cy7, and Cy7.5.
Cy stands for 'cyanine', and first digit is number of carbon atoms between indolenine groups. Cy2 which is oxazole derivative rather than indolenin, is an exception from this rule. Suffix .5 is added for benzo-fused cyanines. Variation of the structures allows to change fluorescence properties of the molecules, and to cover most important part ot visible and NIR spectrum with several fluorophores.

Most derivatives of non-sulfonated cyanines (except for hydrochlorides of hydrazides and amines) have low aqueous solubility. When these molecules are used for biomolecule labeling, use of organic co-solvent (5-20% of DMF or DMSO) is necessary for efficient reaction. Cyanine dye should be dissolved in organic solvent first, and added to a solution of biomolecule (protein, peptide, amino-labeled DNA) in appropriate aqueous buffer. When conjugation takes place efficiently, the dye reacts before it precipitates.

Fluorescent properties of non-sulfonated cyanines have little dependence on solvent and surrounding. Absorbance and fluorescence spectra of non-sulfonated cyanine dyes are plotted below.

Lumiprobe Citations using Lumiprobe's sulfo - cyanine dyes for nanotechnology

a few examples of

Sulfo-Cyanine3 NHS ester

1. Glembockyte, V.; Lincoln, R.; Cosa, G. Cy3 Photoprotection Mediated by Ni²⁺ for Extended Single-Molecule Imaging: Old Tricks for New Techniques. Journal of the American Chemical Society, 2015, 137(3), 1116–1122. doi: 10.1021/ja509923e
2. Graen, T.M.D.; Hoefling, M.; Grubmüller, H. AMBER-DYES: Characterization of Charge Fluctuations and Force Field Parameterization of Fluorescent Dyes for Molecular Dynamics Simulations. Journal of Chemical Theory and Computation, 2014, 10(12), 5505-5512. doi: 10.1021/ct500869p
3. Wang, W.; Ji, X.; Na, H.B.; Safi, M.; Smith, A.; Palui, G.; Perez, J.M.; Mattoussi, H. Design of a Multi-Dopamine-Modified Polymer Ligand Optimally Suited for Interfacing Magnetic Nanoparticles with Biological Systems. Langmuir, 2014, 30(21), 6197-6208. doi: 10.1021/la500974r
4. Aldeek, F.; Muhammed, M.A.H.; Palui, G.; Zhan, N.; Mattoussi, H. Growth of Highly Fluorescent Polyethylene Glycol- and Zwitterion-Functionalized Gold Nanoclusters. ACS Nano, 2013, 7(3), 2509-2521. doi: 10.1021/nn305856t
5. Zhan, N.; Palui, G.; Safi, M.; Ji, X.; Mattoussi, H. Multidentate Zwitterionic Ligands Provide Compact and Highly Biocompatible Quantum Dots. Journal of the American Chemical Society, 2013, 135(37), 13786-13795. doi: 10.1021/ja405010v

Lumiprobe has developed a better process for making sulfo-dyes, and thus offers you much LOWER PRICING on WATER SOLUBLE sulfonated derivatives of cyanines. It includes various derivatives such as NHS esters, maleimides, azides, alkynes, amines, and carboxylic acids. The water-soluble dyes are excellent choice for protein labeling applications, for hydrophilic nanoparticles, and when it is necessary to carry out labeling in aqueous phase avoiding aggregation, and non-specific hydrophobic interactions.

Each reagent page is a resource with information, pricing, availability, absorption and emission spectra, MSDS, and general properties. Lumiprobe's website offer's instantly downloadable Certificate of Analysis (CoA) detailing meticulous quality control, real NMR, UV and mass spectra, and HPLC chromatograms.

• Sulfo-Cyanine3 NHS ester
• Sulfo-Cyanine5 NHS ester
• Sulfo-Cyanine7 NHS ester
• Sulfo-Cyanine3 azide
• Sulfo-Cyanine5 azide
• Sulfo-Cyanine7 azide
• Sulfo-Cyanine3 carboxylic acid
• Sulfo-Cyanine5 carboxylic acid
• Sulfo-Cyanine7 carboxylic acid
• Sulfo-Cyanine3 maleimide
• Sulfo-Cyanine5 maleimide
• Sulfo-Cyanine5 alkyne
• Sulfo-Cyanine7 amine

Reagents can often be customized for your needs 

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Summary of what reagent binds to