TRANSMISSION-LIGHT MICROSCOPY OF STRUCTURALLY COLORED SEMITHIN CARTILAGE SECTIONS

Conversion of osmified tracheal cartilage constituents into an array o f laminar interference gratings hits been attained by three tandem rea ctions. Oxidation of semithin, LR white-embedded cartilage sections by acetic anhydride in dimethyl sulfoxide is the first step in the conve rsion process. Subsequent addition reactions of oxidized cartilage pyr anoses and furanoses with thiocarbohydrazide constitutes the second st ep. Reduction of silver proteinate by thiocarbohydrazones and the conc omitant coating of cartilage constituents with silver gratings complet es the conversion of cartilage sections into a system of layered inter ference filters. In transmitted light, all components of converted car tilage display vivid structural colors, which allow detailed microscop ic analysis of structurally colored cellular and extracellular cartila ge constituents.