SELECTIVE STAINING REACTION OF THE CATIONIC COMPLEX TRIS(1,10-PHENANTHROLINE)-IRON(II) WITH CELL AND TISSUE POLYANIONS

Some metal complexes of hematoxylin and phthalocyanin are widely used in histology and histochemistry, but properties and applications of ot her metal-ligand complexes have been overlooked or scarcely explored. Aqueous solutions of the red cation tris(1,10-phenanthroline)-iron (II ) (abbreviately, Fe-OP) stained intense and selectively cell and tissu e components containing acid glycosaminoglycans (mast cell granules an d cartilage matrix), while nuclei and basophilic cytoplasm only reveal ed a very weak staining. Absorption spectra of Fe-OP either free or bo und to mast cell granules showed a close correspondence. These results suggest interesting applications of Fe-OP as a staining reagent for t he selective visualization of sulfated polyanions.