Experimental Cyanine Red: A New Stain for Nucleic Acids and Acid Mucopolysaccharides

Abstract

A new cationic dye, experimental cyanine red (du Pont), with an absorption maximum of 536 mμ and a pH of 2.9 in 0.5% aqueous solution, is shown to be suitable for staining nucleic acids and tissue materials presumed to contain acid mucopolysaccharides. Mammalian tissues fixed in 10% neutral buffered formalin or Bouin's fluid are dehydrated, embedded in paraffin, sectioned, mounted, deparaffinized, passed through ethanols to water, and stained for 3-30 min in 0.5% experimental cyanine red in water. Differentiation and dehydration in 3 changes (about 1 min each) of n-butanol is followed by clearing in xylene and mounting in resin.