OBSERVATIONS ON THE CHEMICAL REACTION BETWEEN BONE TISSUE AND CHLORAZOL FAST PINK BK

Staining with Chlorazol Fast Pink BK (other trade names: Chlorantine Fast Red 2B, Solantine Pink 4BL, etc.) of human fetal parietal bones and skin collagen purified from the same fetuses was studied. In addition, the substantivity of the dye for achilles tendon collagen and for several other commercial substances was compared. The stained and homogenized bone tissue or collagen was treated with various chemicals, proteolytic enzymes and heat, and attempts were made to detect, using various chromatographic methods (gel filtration and thin layer chromatography), the nature of bonds between the stain and the bone components. The behavior of dye bone and dye collagen compounds was compared with that of the compounds between the dye and model substances, e.g., dextrans with varying degrees of cross-linking (Sephadex), cellulose, elastin, etc. The more tightly cross-linked dextrans adsorbed the dye more strongly than the less tightly cross-linked ones. The adsorption of the dye to purified collagen resembled in many respects its adsorption to bone. Chlorazol Fast Pink BK is bound to bone, collagen and the other substances tested chiefly through the formation of heat-labile and weak chemical bonds, preferably through hydrogen bonds or through van der Waals' attraction. The latter type of binding may be involved particularly in the reaction of the dye to cellulose. The adsorption of the dye to bone, collagen and other substances is favored by the elongated form of the reacting molecules. Under the conditions employed, there is also formation of salt type linkages between dye and collagen.