Evaluation of zinc and magnesium doped 45S5 mesoporous bioactive glass system for the growth of hydroxyl apatite layer

Bioactive glass samples of xZhO(22.4 - x)Na(2)0.46 center dot 1SiO(2)center dot 26.9CaO center dot 2.6P(2)O(5)center dot 2MgO system have been prepared by using the sol gel technique. Investigations of structural and bioactive properties of these samples have been undertaken by using X-ray diffraction, field emission scanning electron microscopy, Raman and energydispersive X-ray spectroscopy, Brunauer, Emmett and Teller technique, thermogravimetry, differential thermal analysis and derivative thermogravimetry methods and pH studies. X-ray diffraction spectra of prepared samples indicate the formation of hydroxyl apatite layer after 7 and 14 days during in vitro analysis. Observed peaks of Raman spectra confirm the growth of hydroxyl apatite layer during in vitro analysis. The formation of apatite phase is responsible for change in the morphology of samples which has been studied by field emission scanning electron microscopy. Ca/P ratio and ion dissolution rate have been evaluated from energy dispersive X-ray spectroscopy results. The observed Ca/P ratio further confirms the growth of apatite layer with time during in vitro analysis. The effect of the addition of zinc on surface area and mesoporous nature of all the samples has been investigated by the Brunauer, Emmett and Teller technique. All glass samples have been found to be thermally stable from thermogravimetry, differential thermal analysis and derivative thermogravimetry techniques. pH studies indicate the non-acidic nature of all the prepared glass samples. Drug release properties of the glass samples have been investigated by using gentamycin as an antibiotic. Prepared samples have shown excellent drug release properties which can be related to the porous nature of the samples. Due to slow dissolution rate, good drug delivery properties and formation of apatite phase within 7 to 14 days, our glass samples can be promising candidates for bone regeneration applications. (C) 2014 Elsevier B.V. All rights reserved.