Porous glass-ceramics with bacteriostatic properties in silver-containing titanium phosphates: Control of release of silver ions from glass-ceramics into aqueous solution

Porous glass-ceramics with the surface phase consisting predominantly of AgTi2(PO4)(3) crystal and the interior phase of LiTi2(PO4)(3) crystal are prepared by exchange of Ag+ ions for Li+ ions. In the present work, the release of Ag+ ions from glass-ceramics into aqueous solutions was investigated. Exchanged Ag+ ions were chemically stable in water. The as-exchanged glass-ceramics released Ag+ ions of 30-45 mu equiv/g into phosphate buffer solution containing Na+ ions. X-ray diffraction analysis showed that silver-containing titanium phosphate crystalline phase in the glass-ceramics did not deteriorate even by heating at 900 degrees C. The amount released from the heated glass-ceramics into the buffer solution was found to decrease drastically by 1-2 mu equiv/g. The heated glass-ceramics showed excellent bacteriostatic properties. Glass-ceramics are expected to be novel bacteriostatic materials which have high thermal resistance and are medically safe.