Titanium addition influences antibacterial activity of bioactive glass coatings on metallic implants

Abstract

In an attempt to combat the possibility of bacterial infection and insufficient bone growth around metallic, surgical implants, bioactive glasses may be employed as coatings. In this work, silica-based and borate-based glass series were synthesized for this purpose and subsequently characterized in terms of antibacterial behavior, solubility and cytotoxicity. Borate-based glasses were found to exhibit significantly superior antibacterial properties and increased solubility compared to their silica-based counterparts, with BRT0 and BRT3 (borate-based glasses with 0 and 15 mol% of titanium dioxide incorporated, respectively) outperforming the remainder of the glasses, both borate and silicate based, in these respects. Atomic Absorption Spectroscopy confirmed the release of zinc ions (Zn2+), which has been linked to the antibacterial abilities of glasses SRT0, BRT0 and BRT3, with inhibition effectively achieved at concentrations lower than 0.7 ppm. In vitro cytotoxicity studies using MC3T3-E1 osteoblasts confirmed that cell proliferation was affected by all glasses in this study, with decreased proliferation attributed to a faster release of sodium ions over calcium ions in both glass series, factor known to slow cell proliferation in vitro.

Comparative biological assessments of endodontic root canal sealer containing surface pre-reacted glass-ionomer (S-PRG) filler or silica filler

“…Furthermore, fluoride ion application to a wound dressing remarkably reduces bacterial growth and promotes cell proliferation 16) . In addition, bioactive glass including borate is more resistant to Escherichia coli than silica-based glass 17) . Antibacterial effects of fluoride and borate were reported to promote wound healing as a secondary effect 18,19) .…”

Borate and Silicate Bioactive Glass Coatings Prepared by Nanosecond Pulsed Laser Deposition

“…No significant differences were detected for the 13-93 and 13-93-B3 coatings, while the The effect of the 13-93 and 13-93-B3 BG coated Ti on various microorganisms (E. faecalis, E. coli, P. aeruginosa, S. aureus) was evaluated after incubation at 37 °C for 24 h. The results of the OD600 nm measured with a BioPhotometer are shown in Figure 7, where the OD values are properly multiplied for the dilution factor. It is possible to note that even if borate glasses should have antibacterial properties, as follows from the literature [28][29][30], all microbiology tests show a rather high Figure 6. Optical microscopic images taken after staining with Alizarin Red S of ADMSCs cultured in the presence of (a,b) 13-93 BG coated Ti, (c,d) 13-93-B3 BG coated Ti in osteogenic medium, (e,f) positive control and (g,h) negative control (ADMSCs cultured with or without osteogenic medium, respectively) for three weeks.…”

“…To obtain crystalline films, nanosecond PLD deposition is usually performed by the heating of the substrate or by using a buffer gas [41,44,45], so we can expect that also the deposited films are amorphous. We deposited the films at room temperature since it was demonstrated that amorphous materials show superior solubility in biological or simulated biological fluid media and are characterized by an increased bioactivity with respect to crystalline materials [8,9,29,46].…”

“…Some studies evidenced that boron influences osteogenic differentiation of mesenchymal stem cells [24,25], being also angiogenic [26]. Many studies report that ion doping enhances the antibacterial properties of borate based bioglass [27][28][29][30]. On the other hand, Fu and collaborators [31] observed no beneficial effect on cell proliferation during in vitro testing, supposing an overly fast boron release in culture medium, while no toxic effects were found during in vivo testing due to the more dynamic microenvironment of the organism, which allows a rapid metabolization of boron.…”

“…Many of the coatings' techniques require high temperature treatment in order to allow the glass to react with the substrate surface [32][33][34]. In this contest, borate glasses are advantageous with respect to silicate ones since boron oxide reduces the coefficient of thermal expansion of glass, better matching the coefficient of thermal expansion of metal substrate [29].…”