Toxicity of silica-containing calcium phosphate glasses demonstrated in mice

Abstract

Suspensions of calcium phosphate glass containing various concentrations of silica (glass composition (moles): 100 Ca(PO 3) 2 to x SiO 2, x = 0, 5, 10, 15 or 40) dispersed in normal saline were injected intraperitoneally into C57BL/6 mice to determine the mortality within 30 days. The mortality was 0 10 , 3 10 , 9 10 , 10 10 and 10 10 at x = 0, 5, 10, 15 and 40 mol silica, respectively. By means of inductively coupled plasma analysis, the amount of dissolved silica (Si 4+) in water at 37°C from the calcium phosphate glass depended on the amount of silica in the glasses. The mortality of mice was directly proportional to the silica content of the glass injected intraperitoneally. These results clearly show that the dissolved silica (Si 4+) from the glass, monomeric or low molecular silicic anion, is highly toxic. The SiO 2 component in biomaterials has toxic potential when dissolved in the body.