FIXATION OF CELLS AND TISSUES BY CHLORO-S-TRIAZINES

Abstract

Cyanuric chloride and related water-soluble dichloro-s-triazines (Procion dyes and Lissatan PR) or monochloro-s-triazines (Procion H and Cibacron dyes, were utilized as fixatives for fresh and freeze-dried animal tissues. With these reagents, endogenous and exogenous substances were irreversibly insolubilized and rendered resistant to chemical and enzymatic degradation. Certain components have been preserved heretofore lost by other methods. Fixation may depend mainly on the formation of covalent and chelate bonds with the tissue colloids. These chloro-s-triazines can be applied in various ways to meet specific fixation needs. In order to avoid the effects of solvents, cells and thin segments of tissues can be cyanurated in the vapors of cyanuric chloride. The water-soluble Procion dyes and Lissatan PR are effective fixatives for some constituents in fresh tissues; enamel matrix is especially well preserved. The most effective of these cyanurating agents for general use appears to be cyanuric chloride in nonpolar solvents when applied to freeze-dried tissues. Following some cyanurations, unreacted striazine halogen appears available for further condensation with active hydrogen in reactants containing certain functional groups (i.e.,—NH₂, —SH, —OH, etc.) By condensations with suitable reactants it appears possible to establish crosslinked polymers in tissues. There is evidence that reaction of fresh hydrated tissues with dichloro-s-triazines imparted some water-repellency to the tissues. Through unreacted halogen in the previously condensed s-triazinyl rings, it appears possible at ambient temperature to effect additional condensations with water-soluble agents utilized in hydrophobing treatments.