Gareth J Owens | University of Liverpool (original) (raw)

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Papers by Gareth J Owens

Research paper thumbnail of Novel sol–gel preparation of (P2O5)0.4–(CaO)0.25–(Na2O)X–(TiO2)(0.35−X) bioresorbable glasses (X = 0.05, 0.1, and 0.15)

Journal of Sol-Gel Science and Technology, 2014

Quaternary phosphate-based glasses in the P 2 O 5 -CaO-Na 2 O-TiO 2 system with a fixed P 2 O 5 a... more Quaternary phosphate-based glasses in the P 2 O 5 -CaO-Na 2 O-TiO 2 system with a fixed P 2 O 5 and CaO content of 40 and 25 mol% respectively have been successfully synthesised via sol-gel method and bulk, transparent samples were obtained. The structure, elemental proportion, and thermal properties of stabilised solgel glasses have been characterised using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), 31 P nuclear magnetic resonance ( 31 P NMR), titanium K-edge X-ray absorption near-edge structure (XANES), fourier transform infrared (FTIR) spectroscopy, and differential thermal analysis (DTA). The XRD results confirmed the amorphous nature for all stabilized sol-gel derived glasses. The EDX result shows the relatively low loss of phosphorus during the sol-gel process and Ti K-edge XANES confirmed titanium in the glass structure is in mainly sixfold coordination environment. The 31 P NMR and FTIR results revealed that the glass structure consist of mainly Q 1 and Q 2 phosphate units and the Ti 4+ cation was acting as a cross-linking between phosphate units. In addition DTA results confirmed a decrease in the glass transition and crystallisation temperature with increasing Na 2 O content. Ion release studies also demonstrated a decrease in degradation rates with increasing TiO 2 content therefore supporting the use of these glasses for biomedical applications that require a degree of control over glass degradation. These sol-gel glasses also offer the potential to incorporate proactive molecules for drug delivery application due to the low synthesis temperature employed.

Research paper thumbnail of Role of gallium and silver from phosphate-based glasses on in vitro dual species oral biofilm models of Porphyromonas gingivalis and Streptococcus gordonii

Phosphate-based glasses (PBGs) are excellent controlled delivery agents for antibacterial ions su... more Phosphate-based glasses (PBGs) are excellent controlled delivery agents for antibacterial ions such as silver and gallium. The aim of this study was to assess the potential utility of novel PBGs combining both gallium and silver for use in periodontal therapy. To this end, an in vitro biofilm model with the putative periodontal pathogen, Porphyromonas gingivalis, and an initial colonizer, Streptococcus gordonii, was established. The effect of increasing calcium content in gallium-silver-doped PBG on the susceptibility of P. gingivalis was examined. A decrease in degradation rates (30.34, 25.19, 21.40

Research paper thumbnail of Role of gallium and silver from phosphate-based glasses on in vitro dual species oral biofilm models of Porphyromonas gingivalis and Streptococcus gordonii

Acta Biomaterialia, 2012

Phosphate-based glasses (PBGs) are excellent controlled delivery agents for antibacterial ions su... more Phosphate-based glasses (PBGs) are excellent controlled delivery agents for antibacterial ions such as silver and gallium. The aim of this study was to assess the potential utility of novel PBGs combining both gallium and silver for use in periodontal therapy. To this end, an in vitro biofilm model with the putative periodontal pathogen, Porphyromonas gingivalis, and an initial colonizer, Streptococcus gordonii, was established. The effect of increasing calcium content in gallium-silver-doped PBG on the susceptibility of P. gingivalis was examined. A decrease in degradation rates (30.34, 25.19, 21.40

Research paper thumbnail of Novel sol–gel preparation of (P2O5)0.4–(CaO)0.25–(Na2O)X–(TiO2)(0.35−X) bioresorbable glasses (X = 0.05, 0.1, and 0.15)

Journal of Sol-Gel Science and Technology, 2014

Quaternary phosphate-based glasses in the P 2 O 5 -CaO-Na 2 O-TiO 2 system with a fixed P 2 O 5 a... more Quaternary phosphate-based glasses in the P 2 O 5 -CaO-Na 2 O-TiO 2 system with a fixed P 2 O 5 and CaO content of 40 and 25 mol% respectively have been successfully synthesised via sol-gel method and bulk, transparent samples were obtained. The structure, elemental proportion, and thermal properties of stabilised solgel glasses have been characterised using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), 31 P nuclear magnetic resonance ( 31 P NMR), titanium K-edge X-ray absorption near-edge structure (XANES), fourier transform infrared (FTIR) spectroscopy, and differential thermal analysis (DTA). The XRD results confirmed the amorphous nature for all stabilized sol-gel derived glasses. The EDX result shows the relatively low loss of phosphorus during the sol-gel process and Ti K-edge XANES confirmed titanium in the glass structure is in mainly sixfold coordination environment. The 31 P NMR and FTIR results revealed that the glass structure consist of mainly Q 1 and Q 2 phosphate units and the Ti 4+ cation was acting as a cross-linking between phosphate units. In addition DTA results confirmed a decrease in the glass transition and crystallisation temperature with increasing Na 2 O content. Ion release studies also demonstrated a decrease in degradation rates with increasing TiO 2 content therefore supporting the use of these glasses for biomedical applications that require a degree of control over glass degradation. These sol-gel glasses also offer the potential to incorporate proactive molecules for drug delivery application due to the low synthesis temperature employed.

Research paper thumbnail of Role of gallium and silver from phosphate-based glasses on in vitro dual species oral biofilm models of Porphyromonas gingivalis and Streptococcus gordonii

Phosphate-based glasses (PBGs) are excellent controlled delivery agents for antibacterial ions su... more Phosphate-based glasses (PBGs) are excellent controlled delivery agents for antibacterial ions such as silver and gallium. The aim of this study was to assess the potential utility of novel PBGs combining both gallium and silver for use in periodontal therapy. To this end, an in vitro biofilm model with the putative periodontal pathogen, Porphyromonas gingivalis, and an initial colonizer, Streptococcus gordonii, was established. The effect of increasing calcium content in gallium-silver-doped PBG on the susceptibility of P. gingivalis was examined. A decrease in degradation rates (30.34, 25.19, 21.40

Research paper thumbnail of Role of gallium and silver from phosphate-based glasses on in vitro dual species oral biofilm models of Porphyromonas gingivalis and Streptococcus gordonii

Acta Biomaterialia, 2012

Phosphate-based glasses (PBGs) are excellent controlled delivery agents for antibacterial ions su... more Phosphate-based glasses (PBGs) are excellent controlled delivery agents for antibacterial ions such as silver and gallium. The aim of this study was to assess the potential utility of novel PBGs combining both gallium and silver for use in periodontal therapy. To this end, an in vitro biofilm model with the putative periodontal pathogen, Porphyromonas gingivalis, and an initial colonizer, Streptococcus gordonii, was established. The effect of increasing calcium content in gallium-silver-doped PBG on the susceptibility of P. gingivalis was examined. A decrease in degradation rates (30.34, 25.19, 21.40

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