Antimicrobial Activity Evaluation on Silver Doped Hydroxyapatite/Polydimethylsiloxane Composite Layer

The goal of this study was the preparation, physicochemical characterization, and microbiological evaluation of novel hydroxyapatite doped with silver/polydimethylsiloxane (Ag:HAp-PDMS) composite layers. In the first stage, the deposition of polydimethylsiloxane (PDMS) polymer layer on commercially pure Si disks has been produced in atmospheric pressure corona discharges. Finally, the new silver doped hydroxyapatite/polydimethylsiloxane composite layer has been obtained by the thermal evaporation technique. The Ag:HAp-PDMS composite layers were characterized by various techniques, such as Scanning Electron Microscopy (SEM), Glow Discharge Optical Emission Spectroscopy (GDOES), and X-ray photoelectron spectroscopy (XPS). The antimicrobial activity of the Ag:HAp-PDMS composite layer was assessed against Candida albicans ATCC 10231 (ATCC-American Type Culture Collection) by culture based and confirmed by SEM and Confocal Laser Scanning Microscopy (CLSM) methods. This is the first study reporting the antimicrobial effect of the Ag:HAp-PDMS composite layer, which proved to be active against Candida albicans biofilm embedded cells.

Structural properties of silver doped hydroxyapatite and their biocompatibility

The aim of this study was to obtain a novel hydroxyapatite-based material with high biocompatibility. The structural properties of the samples were well characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). The X-ray diffraction studies revealed the characteristic peaks of hydroxyapatite in each sample. Other phases or impurities were not observed. The scanning electron microscopy observations suggest that the doping components have no influence on the surface morphology of the samples, which reveals a homogeneous aspect of the synthesized particles for all samples. The presence of calcium (Ca), phosphor (P), oxygen (O) and silver (Ag) in the Ag:HAp is confirmed by energy dispersive X-ray (EDAX) and X-ray Photoelectron Spectroscopy analyses. Nanocrystalline silver doped HAp stimulated viability and potentiated the activation of murine macrophages.