Antimicrobial and bioactive phosphate-free glass–ceramics for bone tissue engineering applications

Abstract

Glasses with composition 55SiO2-10K2O-(35-x)CaO-xMgO (x = 5, 10, 15 up to 35) were prepared via conventional melt-quench technique. The glasses were converted to glass–ceramics by controlled heat-treatment at 850 °C. Higher content of MgO instead of CaO prevents the devitrification of the glasses. The in-vitro bioactivity of the glasses/glass–ceramics was evaluated in simulated body fluid (SBF). Glasses exhibited better bioactivity than the glass–ceramics. The weight loss and ions leaching profiles (especially potassium ions) of the samples played crucial role in formation of hydroxyapatite layer and its morphology. Hydroxyapatite had Ca/P ratio close to that for natural bone. However, it could not crystallize within experimental time and exhibited amorphous nature in X-ray diffraction. Microhardness of the glasses/glass–ceramics before and after immersion in SBF is also given. Microbial tests reveal that these glasses/glass–ceramics are effective in inhibiting the growth of fungi and do not affect the normal functioning of the antimicrobial drugs.