Antimicrobial Gallium‐Doped Phosphate‐Based Glasses

Abstract

Novel quaternary gallium‐doped phosphate‐based glasses (1, 3, and 5 mol % Ga2O3) were synthesized using a conventional melt quenching technique. The bactericidal activities of the glasses were tested against both Gram‐negative (Escherichia coli and Pseudomonas aeruginosa) and Gram‐positive (Staphylococcus aureus, methicillin‐resistant Staphylococcus aureus, and Clostridium difficile) bacteria. Results of the solubility and ion release studies showed that these glass systems are unique for controlled delivery of Ga3+. 71Ga NMR measurements showed that the gallium is mostly octahedrally coordinated by oxygen atoms, whilst FTIR spectroscopy provided evidence for the presence of a small proportion of tetrahedral gallium in the samples with the highest gallium content. FTIR and Raman spectra also afford an insight into the correlation between the structure and the observed dissolution behavior via an understanding of the atomic‐scale network bonding characteristics. The results confirmed that the net bactericidal effect was due to Ga3+, and a concentration as low as 1 mol % Ga2O3 was sufficient to mount a potent antibacterial effect. The dearth of new antibiotics in development makes Ga3+ a potentially promising new therapeutic agent for pathogenic bacteria including MRSA and C. difficile.

Preparation, structural characterisation and antibacterial properties of Ga-doped sol–gel phosphate-based glass

“…In fact, our own 71 Ga NMR study of CaONa 2 O-Ga 2 O 3 -P 2 O 5 melt-quenched glasses with a P/Ga > 9 detected only octahedral gallium. [6] High-energy X-ray diffraction data gives information on the structure of a material by revealing the correlations between the atoms present. The parameters that define these correlations, i.e.…”

“…These results suggest that Gadoped PBG is a potentially promising new therapeutic agent for pathogenic bacteria including MRSA and C. difficile. [6] Here we have prepared Ga-doped PBG by a sol-gel route which, to the best of our knowledge, is the first report of such a preparation. The method is based upon that which we developed to prepare biocompatible, bioresorbable, sol-gel (CaO) 0.3 (Na 2 O) 0.2 (P 2 O 5 ) 0.5 glass [12] with the addition of gallium ethoxide as the Ga…”

“…[5] Recently, we have shown that phosphate-based glasses (PBGs) in the system CaO-Na 2 O-P 2 O 5 system provide a means to deliver Ga 3+ ions in a controlled way. [6] Phosphate-based glasses have predictable dissolution rates that can be manipulated via chemical composition to give materials that degrade over a period of a few hours to those that are stable for over one year. Furthermore, PBGs containing calcium and sodium are both biocompatible and bioresorbable.…”

Glasses in bone regeneration: A multiscale issue

“…In particular our group has been very interested in the last few years in the substitution of MBGs by (i) up to 3.5% Ce2O3, because it was reported that Ce 3+ ions reduce the enamel demineralization, and are neuroprotective [19], (ii) up to 3.5% Ga2O3, because it was published that Ga 3+ ions increase the calcium content in bone, and are antimicrobial [20], and (iii) ZnO because, in addition to other biological functions, it was reported that Zn 2+ ions stimulates the bone formation and exhibit also a bactericide action [21,22]. In the …”

Tailoring Cell Behavior on Polymers by the Incorporation of Titanium Doped Phosphate Glass Filler

“…[16,[19][20][21][22][23][24][25][26] Other interesting materials are phosphate glasses, which have readily tuneable properties to improve cellular activity [27][28][29][30][31] or inhibit biofilm formation (antimicrobial glasses). [32][33][34] To date they were rarely used as polymer fillers. Glass fibers reinforced polymers have been shown to have highly desirable both biological and mechanical properties, therefore glass fillers as a powder/particles seem to be alternative for other used fillers.…”