Toluidine blue staining of cartilage proteoglycan subunits.

Selective binding of toluidine blue to basophilic proteoglycans is the first stage of a staining method which proceeds to the formation of a heavy metal salt of the dyestuff. By means of this procedure matrix complexes of hyalin cartilage were stained such as to display granular subunits about 25 to 35 A in diameter. The findings are interpreted as the demonstration of proteoglycan constituents of chondromucin aggregates.