Detection and localization of silicon and associated elements in vertebrate bone tissue by imaging ion microscopy

The growing long bones from normal embryonic chicks and young rats have been examined in situ by imaging ion microscopy, a highly sensitive technique for elemental detection and localization. In tibial diaphyses from chick and rat, treated with anhydrous ethylene glycol, embedded in Spurr medium, and dry sectioned 1-2 microns thick, analyses revealed the presence of silicon, calcium, magnesium, carbon, and oxygen. Silicon localization was principally extracellular in the tissues. Comparison of single element maps of silicon and calcium indicated that silicon specifically appeared in putative uncalcified osteoid regions of tibiae. Detection and imaging of silicon by ion microscopy support results of earlier work by Carlisle, who demonstrated the element in osteoid of rat and mouse bone by electron probe microanalysis. The current data offer the possibility for characterizing more completely silicon interaction in vertebrate calcified tissues.