Photocatalytical Antibacterial Activity of Mixed-Phase TiO2 Nanocomposite Thin Films against Aggregatibacter actinomycetemcomitans

Advances in the superhydrophilicity-modified titanium surfaces with antibacterial and pro-osteogenesis properties: A review

In recent years, the rate of implant failure has been increasing. Microbial infection was the primary cause, and the main stages included bacterial adhesion, biofilm formation, and severe inhibition of implant osseointegration. Various biomaterials and their preparation methods have emerged to produce specific implants with antimicrobial or bactericidal properties to reduce implant infection caused by bacterial adhesion and effectively promote bone and implant integration. In this study, we reviewed the research progress of bone integration promotion and antibacterial action of superhydrophilic surfaces based on titanium alloys. First, the adverse reactions caused by bacterial adhesion to the implant surface, including infection and bone integration deficiency, are briefly introduced. Several commonly used antibacterial methods of titanium alloys are introduced. Secondly, we discuss the antibacterial properties of superhydrophilic surfaces based on ultraviolet photo-functionalization and plasma treatment, in contrast to the antibacterial principle of superhydrophobic surface morphology. Thirdly, the osteogenic effects of superhydrophilic surfaces are described, according to the processes of osseointegration: osteogenic immunity, angiogenesis, and osteogenic related cells. Finally, we discuss the challenges and prospects for the development of this superhydrophilic surface in clinical applications, as well as the prominent strategies and directions for future research.

Antibacterial Activity of an Anodized TiNbSn Alloy Prepared in Sodium Tartrate Electrolyte

In this study, we anodized a TiNbSn alloy with low Young’s modulus in an electrolyte of sodium tartrate with and without hydrogen peroxide (H2O2). The photo-induced characteristics of the anodized alloy were analyzed for crystallinity and electrochemical conditions with comparisons to the effect with the addition of H2O2. The antibacterial activity was evaluated using methicillin-resistant Staphylococcus aureus and other pathogenic bacteria according to ISO 27447, and time decay antibacterial tests were also conducted. The anodized oxide had a porous microstructure with anatase- and rutile-structured titanium dioxide (TiO2). In contrast, the peaks of rutile-structured TiO2 were accelerated in the anodized TiNbSn alloy with H2O2. The formation of hydroxyl radicals and methylene blue breaching performance under ultraviolet irradiation was confirmed in the anodic oxide on TiNbSn alloy with and without H2O2. The anodic oxide on TiNbSn alloy had a robust antibacterial activity, and no significant difference was detected with or without H2O2. We conclude that anodized TiNbSn alloy with sodium tartrate electrolyte may be a functional biomaterial with a low Young’s modulus and an antibacterial function.

Titanium industrial residues surface modification towards its reuse as antimicrobial surfaces

In this study, a new material obtained from titanium ingots residue was coated with natural carotenoids having antibacterial properties. The waste is a no recycling titanium scrap from technological production process which was pressed and transformed into disks titanium samples. Through anodization and annealing procedures of the titanium disk, a nanostructured titanium dioxide surface with photocatalytic and antibacterial properties was successfully obtained. The titanium scrap impurities (V, Al, and N), unwanted for production process, have shown to improve electrochemical and semiconductor properties of the residue surfaces. The nanostructured titanium scrap surface was modified with two different carotenoids, torularhodin and β-carotene, to potentiate the antibacterial properties. The bactericidal tests were performed against Salmonella typhimurium and Escherichia coli, both Gram-negative. The best bactericidal effect is obtained for nanostructured titanium scrap disks immersed in torularhodin, with a percentage of growth inhibition around 60% against both tested bacteria. The results suggest that this low-cost waste material is suitable for efficient reuse as antibacterial surface after a few simple and inexpensive treatments.

Visible light-induced antibacterial and osteogenic cell proliferation properties of hydrogenated TiO2 nanotubes/Ti foil composite

We successfully fabricated the hydrogenated TiO₂ nanotubes/Ti foil (H-TNTs/f-Ti) composite via one-step anodization and two-step annealing. H-TNTs/f-Ti composite had a higher visible light-induced photoelectric response and more hydroxyl functional groups compared with Ti foil and unmodified TiO₂ nanotubes/Ti foil composite, which contributed to limiting the proliferation of Streptococcus mutans and Porphyromonas gingivalis, promoting the proliferation of MC3T3-E1 cell on the hydroxylated surface, and improving the biocompatibility with osteogenic cells. Our study provides a simple and effective method for significantly improving dental implant efficacy.

Application of Antimicrobial Nanoparticles in Dentistry

Oral cavity incessantly encounters a plethora of microorganisms. Plaque biofilm-a major cause of caries, periodontitis and other dental diseases-is a complex community of bacteria or fungi that causes infection by protecting pathogenic microorganisms from external drug agents and escaping the host defense mechanisms. Antimicrobial nanoparticles are promising because of several advantages such as ultra-small sizes, large surface-area-to-mass ratio and special physical and chemical properties. To better summarize explorations of antimicrobial nanoparticles and provide directions for future studies, we present the following critical review. The keywords "nanoparticle," "anti-infective or antibacterial or antimicrobial" and "dentistry" were retrieved from Pubmed, Scopus, Embase and Web of Science databases in the last five years. A total of 172 articles met the requirements were included and discussed in this review. The results show that superior antibacterial properties of nanoparticle biomaterials bring broad prospects in the oral field. This review presents the development, applications and underneath mechanisms of antibacterial nanoparticles in dentistry including restorative dentistry, endodontics, implantology, orthodontics, dental prostheses and periodontal field.

Alkaline phosphatase levels of murine pre-osteoblastic cells on anodized and annealed titanium surfaces

Purpose

This study aimed to evaluate the initial adhesion morphology and alkaline phosphatase (ALP) activity of murine pre-osteoblastic MC3T3-E1 cells cultured on anatase/rutile mixed-phase TiO₂ thin films with photocatalytical activity with previously confirmed antibacterial properties.

Materials and methods

Anatase/rutile mixed-phase TiO₂ thin films fabricated by anodization and annealing of cpTi were used to culture MC3T3-E1 cells to evaluate the initial cellular adhesion morphology and ALP activity in vitro.

Results

Compared with MC3T3-E1 cells cultured on cpTi substrates and the control group, cells cultured on anatase/rutile mixed-phase TiO₂ thin films exhibited similar ALP levels after cell culture day 9.

Conclusion

Anodizing and annealing processes fabricate multifunctional surfaces on cpTi with improved osteogenic properties for implants.

Optimal conditions for producing bactericidal sodium hyaluronate-TiO2 bionanocomposite and its characterization

In this research, the creation of optimum conditions for the formation of sodium hyaluronate-TiO₂ bionanocomposite and its antibacterial effect on gram positive and gram negative bacteria was evaluated. The Fourier transform infrared spectroscopy spectra, scanning electron microscopy images and energy dispersive X-ray spectroscopy pattern confirmed the formation of the bionanocomposite. Thermogravimetric analysis and differential thermal analysis indicated that the thermal stability rate had significantly improved with formation of the bionanocomposite. Nine experiments were designed based on the Taguchi method by applying different proportions of sodium hyaluronate biopolymer and TiO₂ nanoparticles at different stirring times. Bionanocomposite produced under conditions of experiment 5 (TiO₂ 4mg/ml, sodium hyaluronate 1mg/ml and stirring time of 90min) and experiment 9 (TiO₂ 8mg/ml, sodium hyaluronate 2mg/ml and stirring time of 60min) completely prevented the growth of Staphylococcus aureus and Escherichia coli. It can be concluded that sodium hyaluronate-TiO₂ bionanocomposite can be used as an effective antimicrobial compound in food, pharmaceutical, medical and environmental sectors.

Enhanced osteogenic activity of anatase TiO2 film: Surface hydroxyl groups induce conformational changes in fibronectin

In this study, with an attempt to identify the effects of TiO₂ crystalline phase compositions on the osteogenic properties, the anatase and rutile TiO₂ thin films with similar film thickness, surface topography and hydrophilicity were prepared on Si (100) substrates by atomic layer deposition (ALD), subsequent thermal annealing and ultraviolet irradiation. The films were studied with XRD, XPS, FE-SEM, AFM, FTIR and contact angle measurements. In vitro cellular assays showed that the anatase phase led to better osteoblast compatibility in terms of adhesion, proliferation, differentiation, mineralization as well as osteogenesis-related gene expression when compared with the rutile phase. We investigated the difference between the anatase and rutile TiO₂ films at the biomolecular level to explain the enhanced osteogenic activity of the anatase film. It was found that the presence of more TiOH groups on anatase surface induced more cell-binding sites of fibronectin (FN) exposed on its surface, causing a more active conformation of the adsorbed FN for subsequent osteoblast behaviors.