Papers by Author: Lasma Poca

Abstract: In the present study, the in vitro bioactivity of silver-doped hydroxyapatite (HAp/Ag) scaffolds was investigated. HAp/Ag was prepared using two different modified wet precipitation methods. The X-ray powder diffraction (XRD) results showed, that sintered HAp/Ag samples prepared using method (I) contain two phases HAp and Ag, but samples prepared by method (II) contain three different phases - HAp, Ag and AgO. After 2 month incubation period in simulated body fluid (SBF), surface of HAp/Ag scaffolds was coated with bone-like apatite. Thickness of bone-like apatite layer increased from 2 μm up to 32 μm, increasing the incubation period.

Abstract: Modification of surface morphology and composition of niobophosphate glass and glass-ceramic in the system P₂O₅-CaO-Nb₂O₅-Na₂O was investigated. Amorphous, partly crystalline and crystalline samples were prepared in shape of pellet with diameter 10 mm. Samples were treated in 1 and 5 days in citric acid at 37°C and 3h in boiling HCl. Surface morphology before and after treatment was investigated by scanning electron microscopy (SEM), phase composition by X-ray powder diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). Glass sample was smooth, after treatment in citric acid it had cracks and pit-holes on the surface. Partly crystalline sample was smooth and contained inclusions of crystalline Ca₃(PO₄)₂ and Ca₂P₂O₇. Platy crystals of Ca₃(PO₄)₂ dissolved first, than bulky Ca₂P₂O₇. Crystalline samples contained Na₄Nb₈P₄O₃₂ and calcium phosphate phases; surface was rough before and after treatment. EDX showed that amount of phosphorous is proportional to amount of calcium and inversely proportional to amount of sodium and niobium in glass-ceramic samples.