Silver-doped Calcium Phosphate bone cements with antibacterial properties

Calcium phosphate bone cements (CPCs) with antibacterial properties are demanded for clinical applications. In this study, we demonstrated the use of a relatively simple processing route based on preparation of silver-doped CPCs (CPCs-Ag) through the preparation of solid dispersed active powder phase. Real-time monitoring of structural transformations and kinetics of several CPCs-Ag formulations (Ag = 0 wt %, 0.6 wt % and 1.0 wt %) was performed by the Energy Dispersive X-ray Diffraction technique. The partial conversion of β-tricalcium phosphate (TCP) phase into the dicalcium phosphate dihydrate (DCPD) took place in all the investigated cement systems. In the pristine cement powders, Ag in its metallic form was found, whereas for CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, CaAg(PO₃)₃ was detected and Ag (met.) was no longer present. The CPC-Ag 0 wt % cement exhibited a compressive strength of 6.5 ± 1.0 MPa, whereas for the doped cements (CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt %) the reduced values of the compressive strength 4.0 ± 1.0 and 1.5 ± 1.0 MPa, respectively, were detected. Silver-ion release from CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, measured by the Atomic Emission Spectroscopy, corresponds to the average values of 25 µg/L and 43 µg/L, respectively, rising a plateau after 15 days. The results of the antibacterial test proved the inhibitory effect towards pathogenic Escherichia coli for both CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, better performances being observed for the cement with a higher Ag-content

Zinc-releasing calcium phosphate cements for bone substitute materials

The goal of the present study was to develop zinc-doped calcium phosphate bone cements (CPCs-Zn) for functionalized bone grafts applications. An aqueous co-precipitation process for synthesis of beta-tricalcium phosphate (beta-TCP)powder samples with Zn addition ranging from 0 wt% up to 1.2 wt% was proposed as an alternative approach to produce CPCs-Zn, instead of mechanical mixing of powders. Real-time monitoring of structural transformations and kinetics of CPCs-Zn (Zn = 0 wt%, 0.6 wt% and 1.2 wt%) was carried out by the Energy Dispersive X-Ray Diffraction technique. The microstructure development in CPCs-Zn was investigated by Scanning Electron Microscopy. Zn-ion release from CPC-Zn 0.6 wt% and CPC-Zn 1.2 wt% cements, measured by the Atomic Emission Spectroscopy, corresponded to the average values of 0.30 +/- 0.01 and 0.10 +/- 0.01 mu g/L, respectively. The results of antibacterial tests proved the inhibitory effect towards pathogenic Escherichia coli only for the CPC-Zn 0.6 wt% cement formulation. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved

Науки о Земле и Цивилизация

Коллективная монография, подготовленная по материалам XI Международной конференции «Науки о Земле и Цивилизация», посвящена проблемам отношений окружающей среды и общества. Адресуется специалистам в области наук о Земле и естественнонаучного образования, студентам, аспирантам и преподавателям вузов