Cyanine dyes
Cyanine dyes are molecules containing polymethine bridges between two nitrogen atoms with a delocalized charge which have been used for many years as dyes in life science. Since the Cy3, Cy5 and Cy7 were made commercially available as succinimidyl esters in the early 1990s, cyanine dyes began to be used widely as labels for nucleic acids. Because of the good properties of low non-specific binding to biomolecules and bright fluorescence owing to their huge extinction coefficients and good quantum yields, the Cy dyes have been widespread used in DNA and RNA labelling. Cyanine dyes can be divided into two groups based on water solubility: non-sulfonated cyanines and sulfonated cyanines.
Non-sulfonated cyanines
Available non-sulfonated dyes include Cy3, Cy3.5, Cy5, Cy5.5, Cy7, and Cy7.5. Cy stands for 'cyanine', and the first digit identifies the number of carbon atoms between the indolenine groups. The suffix .5 is added for benzo-fused cyanines. Most derivatives of non-sulfonated cyanines have low aqueous solubility except for hydrochlorides of hydrazides and amines. They are organic co-solvent soluble (5-20% of DMF or DMSO). When these molecules are used for biomolecule labeling, they should be dissolved in organic solvent first, and added to a solution of biomolecule (protein, peptide, amino-labeled DNA) in appropriate aqueous buffer. Fluorescent properties of non-sulfonated cyanines have little dependence on solvent and surrounding.
Sulfonated cyanines
Available sulfonated cyanines include sulfo-Cy3, sulfo-Cy5, and sulfo-Cy7, which have additional sulfo-groups that facilitate dissolution of dye molecules in aqueous phase. Charged sulfonate groups decrease aggregation of dye molecules and heavily labeled conjugates. Sulfonated cyanines are highly water soluble, and they do not use organic co-solvent for the labeling in aqueous environment.
- A8773 Cy5 Bis NHS esterSummary: 荧光染料,含有两个氨基反应基团,溶于水
- A8772 Cy3 Bis NHS esterSummary: 荧光染料,含有两个氨基反应基团,溶于水
- A8777 Cy5 carboxylic acid(Et)Summary: 非反应性荧光团,用于对照实验和校准 ,溶于水
- A8776 Cy3 carboxylic acid(Et)Summary: 非反应性荧光团,用于对照实验和校准 ,溶于水
- A8765 Cy3 NHS ester(Et)Summary: 氨基反应性荧光染料,溶于水
- A8262 Cy3.5 alkyne (non-sulfonated)Summary: 用于点击化学反应的染料炔
- A8263 Cy5.5 alkyne (non-sulfonated)Summary: 远红外/近红外染料,用于点击化学标记
- A8260 Cyanine3.5 carboxylic acidSummary: 非反应性的参考染料或对照