dye

A stain or coloring matter; a compound consisting of chromophore and auxochrome groups attached to one or more benzene rings, its color being due to the chromophore and its dyeing affinities to the auxochrome. Dyes are used for intravital coloration of living cells, staining tissues and microorganisms, as antiseptics and germicides, and some as stimulants of epithelial growth. For individual dyes, see the specific names. Commonly but improperly used for radiographic contrast medium. [A.S. deah, deag]

- acidic dyes dyes that ionize in solution to produce negatively charged ions or anions; they consist of sodium salts of phenols and carboxylic acid dyes; their solutions tend to be neutral or slightly alkaline; examples are eosin and aniline blue.

- acridine dyes derivatives of the compound acridine that is closely related to xanthene; important as fluorochromes in histology, cytochemistry, and chemotherapy; examples include acriflavine, acridine orange, and quinacrine mustard.

- azin dyes d. derivatives of phenazine that include important histologic stains, such as neutral red, azocarmine G., and safranin O.

- azo dyes dyes in which the azo group is the chromophore and joins benzene or naphthalene rings; they include a large number of biologic stains, such as Congo red and oil red O; also used clinically to promote epithelial growth in the treatment of ulcers, burns, and other wounds; many have anticoagulant action.

- azocarmine dyes dyes giving a dark purplish red color as histologic stains.

- basic dyes dyes which ionize in solution to give positively charged ions or cations; the auxochrome group is an amine which can form a salt with an acid like HCl; solutions are usually slightly acidic; examples include basic fuchsin and toluidine blue O.

- chlorotriazine dyes dyes containing one or more chlorotriazine moieties that react with polysaccharides.

- diphenylmethane dyes dyes in which the central carbon connecting two phenyl groups lacks an amino or imino group; the chromophore is the quinoid ring; an alternative formulation is as a ketonimide; the most common example is auramine O.

- ketonimine dyes dyes in which the chromophore is =C=NH connected to two benzene rings; alkylamino groups are added para to the methane carbon on both rings. The most important member for biological purposes is auramine O; an alternative formulation is as a diphenylmethane d..

- natural dyes dyes obtained from animals or plants; examples include carmine, obtained from cochineal in the dried female insect Dactylopius coccus of Central America, and hematoxylin, extracted from the bark of the logwood tree Haematoxylon campechianum in the Caribbean area.

- nitro dyes dyes in which the chromophore is —NO₂, which is so acidic that all dyes in this group are of the acid type; important examples in cytoplasmic staining are picric acid and naphthol yellow S.

- oxazin dyes similar to azin dyes except that one of the connecting N atoms is replaced by O; most important representatives are brilliant cresyl blue, orcein, litmus, and cresyl violet.

- rosanilin dyes several triaminotriphenylmethane dyes or mixtures of them often sold under the name of basic fuchsin; rosanilin dyes differ from other triphenylmethane dyes in that the amino groups are unsubstituted, and they may have methyl groups introduced directly onto the benzene rings; the four possible such dyes are pararosanilin, rosanilin, new fuchsin, and magenta II.

- salt d. SYN: neutral stain.

- synthetic dyes organic d. compounds originally derived from coal-tar derivatives; presently produced by synthesis from benzene and its derivatives; examples include eosin, methylene blue, and fluorescein.

- thiazin dyes similar to azin dyes except that one of the connecting N atoms is replaced by S; includes many important biologic stains, especially in hematology, e.g., azure A, azure B, and methylene blue.

- triphenylmethane dyes a group of dyes that includes pararosanilin, as well as many others used in histology and cytology; employed as nuclear, cytoplasmic, and connective tissue stains; important in histochemistry as in the preparation of Schiff reagent.

- xanthene dyes derivatives of the compound xanthene; include the pyronins, rhodamines, and fluoresceins.

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dye 'dī n

1) color from dyeing

2) a soluble or insoluble coloring matter

dye vb, dyed; dye·ing vt

1) to impart a new and often permanent color to esp. by impregnating with a dye

2) to impart (a color) by dyeing <\dyeing blue on yellow> vi to take up or impart color in dyeing

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(di) any of various colored substances that contain auxochromes and thus are capable of coloring substances to which they are applied; used for staining and coloring, as test reagents, and as therapeutic agents in medicine.