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Metallomics : Integrated Biometal... Apr 2017Despite the ubiquitous nature of titanium(iv) and several examples of its beneficial behavior in different organisms, the metal remains underappreciated in biology.... (Review)
Review
Despite the ubiquitous nature of titanium(iv) and several examples of its beneficial behavior in different organisms, the metal remains underappreciated in biology. There is little understanding of how the metal might play an important function in the human body. Nonetheless, a new insight is obtained regarding the molecular mechanisms that regulate the blood speciation of the metal to maintain it in a nontoxic and potentially bioavailable form for use in the body. This review surveys the literature on Ti(iv) application in prosthetics and in the development of anticancer therapeutics to gain an insight into soluble Ti(iv) influx in the body and its long-term impact. The limitation in analytical tools makes it difficult to depict the full picture of how Ti(iv) is transported and distributed throughout the body. An improved understanding of Ti function and its interaction with biomolecules will be helpful in developing future technologies for its imaging in the body.
Topics: Animals; Antineoplastic Agents; Humans; Microscopy; Models, Molecular; Neoplasms; Optical Imaging; Positron-Emission Tomography; Prostheses and Implants; Titanium
PubMed: 28164202
DOI: 10.1039/c6mt00223d -
Molecules (Basel, Switzerland) Dec 2012Titanium complexes have been widely used as catalysts for C‑C bond-forming processes via free-radical routes. Herein we provide an overview of some of the most... (Review)
Review
Titanium complexes have been widely used as catalysts for C‑C bond-forming processes via free-radical routes. Herein we provide an overview of some of the most significant contributions in the field, that covers the last decade, emphasizing the key role played by titanium salts in the promotion of selective reactions aimed at the synthesis of multifunctional organic compounds, including nucleophilic radical additions to imines, pinacol and coupling reactions, ring opening of epoxides and living polymerization.
Topics: Catalysis; Epoxy Compounds; Free Radicals; Imines; Molecular Structure; Organometallic Compounds; Polymerization; Titanium
PubMed: 23519248
DOI: 10.3390/molecules171214700 -
PloS One 2018Micro- or nano-topography can both provide antimicrobial properties and improve osseointegration of dental implant titanium surfaces. Laser treatment is one of the best...
INTRODUCTION
Micro- or nano-topography can both provide antimicrobial properties and improve osseointegration of dental implant titanium surfaces. Laser treatment is one of the best surface microtexturing techniques. The aim of this study was to evaluate in vitro and in situ biofilm formation on a laser-treated titanium surface, comparing it with two conventional surfaces, machined and grit-blasted.
METHODS
For the in vitro experiment, an oral microcosm biofilm model was developed on the surface of titanium disks and reference human enamel using a bioreactor for 48 h. For the in situ experiment, titanium implants with laser-treated, machined and grit-blasted surfaces were mounted on intraoral trays and worn by ten volunteers for 48 h. Biofilm formation was quantitatively evaluated, and surfaces were analyzed using confocal laser scanning microscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy.
RESULTS–IN VITRO STUDY
Biofilm structures with a prevalence of viable cells covered most of the machined, grit-blasted and human enamel surfaces, whereas less dense biofilm structures with non-confluent microcolonies were observed on the laser-treated titanium. Laser-treated titanium showed the lowest biofilm formation, where microorganisms colonized the edges of the laser-created pits, with very few or no biofilm formation observed inside the pits.
RESULTS–IN SITU STUDY
The biofilm formation pattern observed was similar to that in the in vitro experiment. Confocal laser scanning microscopy showed complete coverage of the implant threads, with mostly viable cells in grit-blasted and machined specimens. Unexpectedly, laser-treated specimens showed few dead microbial cells colonizing the bottom of the threads, while an intense colonization was found on the threading sides.
CONCLUSION
This data suggests that laser-created microtopography can reduce biofilm formation, with a maximum effect when the surface is blasted orthogonally by the laser beam. In this sense the orientation of the laser beam seems to be relevant for the biological interaction with biofilms.
Topics: Biofilms; Dental Enamel; Dental Implants; Humans; Lasers; Microscopy, Confocal; Microscopy, Electron, Scanning; Mouth; Osseointegration; Surface Properties; Titanium
PubMed: 30192766
DOI: 10.1371/journal.pone.0202262 -
Toxicology Letters Mar 2019There is an ongoing discussion on the influence of surface-modifications on the toxicity of commercial particulate materials and how alterations in physical-chemical... (Review)
Review
What is the impact of surface modifications and particle size on commercial titanium dioxide particle samples? - A review of in vivo pulmonary and oral toxicity studies - Revised 11-6-2018.
There is an ongoing discussion on the influence of surface-modifications on the toxicity of commercial particulate materials and how alterations in physical-chemical properties of surfaces impact toxicity. Titanium dioxide (TiO) is a poorly soluble particulate material of significant socioeconomic importance that largely exists as surface-modified particle-types in commerce. The observed toxicological effects of TiO are primarily due to particle effects rather than substance chemistry, as such TiO is commonly considered to be a poorly soluble low toxicity (PSLT) particle. This review provides an overview of the effect of surface modifications on the pulmonary and oral toxicity of commercial TiO particles with emphasis on in vivo studies with appropriate controls, and where both surface modified and untreated materials are present in the same study. Published literature findings involving pulmonary and oral exposures to surface modified TiO particles were reviewed and evaluated for quality and commercial relevance. Suitable publications involving animal studies were identified and summarized. Several studies were identified that have evaluated commercially-relevant surface-modified forms of titanium dioxide with appropriate data quality and with direct comparison to untreated counterparts. Hydrophilic inorganic surface modifications including silica, alumina/alumina hydroxide depositions have been tested along with common hydrophilic and hydrophobic-organic surface treatments. The results for both pigmentary and nanoscale materials demonstrate similar behaviour and indicate limited impact of particle size, surface chemistry, surface charge and surface wettability on observed pulmonary or oral toxicity effects. The low intrinsic toxicity of the TiO base particle and evaluated surface modifications may account for the observed outcomes. A few published studies have drawn different conclusions; however, these were either not conducted using commercial TiO samples (with surface coatings), had several confounding variables to investigate, or were carried out using mouse strains. The differences in experimental designs are described. The identified pulmonary and oral toxicity studies largely indicate that surface modifications and particle size alone have little or no impact on the lung toxicity of TiO particles, following pulmonary exposures when all constituent materials are comprised of chemicals of low specific toxicity particles. In addition, based upon the results of 2 oral toxicity studies, one with surface treated TiO particles (OECD 408) and one without surface treated (OECD 407) TiO particles, there appears to have been no adverse impact on toxicity with the surface-coated material, as both studies produced no adverse effects at the very high doses tested.
Topics: Administration, Inhalation; Administration, Oral; Animals; Dose-Response Relationship, Drug; Humans; Inhalation Exposure; Lung; Lung Diseases; Metal Nanoparticles; Particle Size; Risk Assessment; Surface Properties; Titanium; Toxicity Tests
PubMed: 30468858
DOI: 10.1016/j.toxlet.2018.11.008 -
ACS Nano May 2022Surface topography on the scale of tens of nanometers to several micrometers substantially affects cell adhesion, migration, and differentiation. Recent studies using...
Surface topography on the scale of tens of nanometers to several micrometers substantially affects cell adhesion, migration, and differentiation. Recent studies using electron microscopy and super-resolution microscopy provide insight into how cells interact with surface nanotopography; however, the complex sample preparation and expensive imaging equipment required for these methods makes them not easily accessible. Expansion microscopy (ExM) is an affordable approach to image beyond the diffraction limit, but ExM cannot be readily applied to image the cell-material interface as most materials do not expand. Here, we develop a protocol that allows the use of ExM to resolve the cell-material interface with high resolution. We apply the technique to image the interface between U2OS cells and nanostructured substrates as well as the interface between primary osteoblasts with titanium dental implants. The high spatial resolution enabled by ExM reveals that although AP2 and F-actin both accumulate at curved membranes induced by vertical nanostructures, they are spatially segregated. Using ExM, we also reliably image how osteoblasts interact with roughened titanium implant surfaces below the diffraction limit; this is of great interest to understand osseointegration of the implants but has up to now been a significant technical challenge due to the irregular shape, the large volume, and the opacity of the titanium implants that have rendered them incompatible with other super-resolution techniques. We believe that our protocol will enable the use of ExM as a powerful tool for cell-material interface studies.
Topics: Titanium; Microscopy; Surface Properties; Osseointegration; Osteoblasts
PubMed: 35533401
DOI: 10.1021/acsnano.1c11015 -
International Journal of Molecular... Nov 2018Implant surface characteristics, as well as physical and mechanical properties, are responsible for the positive interaction between the dental implant, the bone and the...
Implant surface characteristics, as well as physical and mechanical properties, are responsible for the positive interaction between the dental implant, the bone and the surrounding soft tissues. Unfortunately, the dental implant surface does not remain unaltered and changes over time during the life of the implant. If changes occur at the implant surface, mucositis and peri-implantitis processes could be initiated; implant osseointegration might be disrupted and bone resorption phenomena (osteolysis) may lead to implant loss. This systematic review compiled the information related to the potential sources of titanium particle and ions in implant dentistry. Research questions were structured in the Population, Intervention, Comparison, Outcome (PICO) framework. PICO questionnaires were developed and an exhaustive search was performed for all the relevant studies published between 1980 and 2018 involving titanium particles and ions related to implant dentistry procedures. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed for the selection and inclusion of the manuscripts in this review. Titanium particle and ions are released during the implant bed preparation, during the implant insertion and during the implant decontamination. In addition, the implant surfaces and restorations are exposed to the saliva, bacteria and chemicals that can potentially dissolve the titanium oxide layer and, therefore, corrosion cycles can be initiated. Mechanical factors, the micro-gap and fluorides can also influence the proportion of metal particles and ions released from implants and restorations.
Topics: Corrosion; Dental Implants; Titanium
PubMed: 30428596
DOI: 10.3390/ijms19113585 -
Accounts of Chemical Research Sep 2021Titanium is an attractive metal for catalytic reaction development: it is earth-abundant, inexpensive, and generally nontoxic. However-like most early transition...
Titanium is an attractive metal for catalytic reaction development: it is earth-abundant, inexpensive, and generally nontoxic. However-like most early transition metals-catalytic redox reactions with Ti are difficult because of the stability of the high-valent Ti state. Understanding the fundamental mechanisms behind Ti redox processes is key for making progress toward potential catalytic applications. This Account details recent progress in Ti-catalyzed (and -mediated) oxidative amination reactions that proceed through formally Ti/Ti catalytic cycles.This class of reactions is built on our initial discovery of Ti-catalyzed [2 + 2 + 1] pyrrole synthesis from alkynes and azobenzene, where detailed mechanistic studies have revealed important factors that allow for catalytic turnover despite the inherent difficulty of Ti redox. Two important conclusions from mechanistic studies are that (1) low-valent Ti intermediates in catalysis can be stabilized through coordination of π-acceptor substrates or products, where they can act as "redox-noninnocent" ligands through metal-to-ligand π back-donation, and (2) reductive elimination processes with Ti proceed through π-type electrocyclic (or pericyclic) reaction mechanisms rather than direct σ-bond coupling.The key reactive species in Ti-catalyzed oxidative amination reactions are Ti imidos (Ti≡NR), which can be generated from either aryl diazenes (RN═NR) or organic azides (RN). These Ti imidos can then undergo [2 + 2] cycloadditions with alkynes, resulting in intermediates that can be coupled to an array of other unsaturated functional groups, including alkynes, alkenes, nitriles, and nitrosos. This basic reactivity pattern has been extended into a broad range of catalytic and stoichiometric oxidative multicomponent coupling reactions of alkynes and other reactive small molecules, leading to multicomponent syntheses of various heterocycles and aminated building blocks.For example, catalytic oxidative coupling of Ti imidos with two different alkynes leads to pyrroles, while stoichiometric oxidative coupling with alkynes and nitriles leads to pyrazoles. These heterocycle syntheses often yield substitution patterns that are complementary to those of classical condensation routes and provide access to new electron-rich, highly substituted heteroaromatic scaffolds. Furthermore, catalytic oxidative alkyne carboamination reactions can be accomplished reaction of Ti imidos with alkynes and alkenes, yielding α,β-unsaturated imine or cyclopropylimine building blocks. New catalytic and stoichiometric oxidative amination methods such as alkyne α-diimination, isocyanide imination, and ring-opening oxidative amination of strained alkenes are continuously emerging as a result of better mechanistic understanding of Ti redox catalysis.Ultimately, these Ti-catalyzed and -mediated oxidative amination methods demonstrate the importance of examining often-overlooked elements like the early transition metals through the lens of modern catalysis: rather than a lack of utility, these elements frequently have undiscovered potential for new transformations with orthogonal or complementary selectivity to their late transition metal counterparts.
Topics: Amination; Catalysis; Models, Molecular; Molecular Structure; Oxidation-Reduction; Titanium
PubMed: 34420307
DOI: 10.1021/acs.accounts.1c00368 -
Clinical Oral Investigations Mar 2022Alterations in the microenvironment of implant surfaces could influence the cellular crosstalk and adhesion patterns of dental implant materials. Cold plasma has been...
BACKGROUND AND OBJECTIVES
Alterations in the microenvironment of implant surfaces could influence the cellular crosstalk and adhesion patterns of dental implant materials. Cold plasma has been described to have an influence on cells, tissues, and biomaterials. Hence, the mechanisms of osseointegration may be altered by non-thermal plasma treatment depending on different chemical compositions and surface coatings of the biomaterial. The aim of the present study is to investigate the influence of cold atmospheric plasma (CAP) treatment on implant surfaces and its biological and physicochemical side effects.
MATERIALS AND METHODS
Dental implant discs from titanium and zirconia with different surface modifications were treated with CAP at various durations. Cell behavior and adhesion patterns of human gingival fibroblast (HGF-1) and osteoblast-like cells (MG-63) were examined using scanning electron microscopy and fluorescence microscopy. Surface chemical characterization was analyzed using energy-dispersive X-ray spectroscopy (EDS). Quantitative analysis of cell adhesion, proliferation, and extracellular matrix formation was conducted including real-time PCR.
RESULTS
CAP did not affect the elemental composition of different dental implant materials. Additionally, markers for cell proliferation, extracellular matrix formation, and cell adhesion were differently regulated depending on the application time of CAP treatment in MG-63 cells and gingival fibroblasts.
CONCLUSIONS
CAP application is beneficial for dental implant materials to allow for faster proliferation and adhesion of cells from the surrounding tissue on both titanium and zirconia implant surfaces with different surface properties.
CLINICAL RELEVANCE
The healing capacity provided through CAP treatment could enhance osseointegration of dental implants and has the potential to serve as an effective treatment option in periimplantitis therapy.
Topics: Dental Implants; Dental Materials; Humans; Microscopy, Electron, Scanning; Osseointegration; Plasma Gases; Surface Properties; Titanium; Zirconium
PubMed: 34907458
DOI: 10.1007/s00784-021-04277-w -
Mikrochimica Acta Jul 2023A bioaccumulation study in red (Palmaria palmata) and green (Ulva sp.) seaweed has been carried out after exposure to different concentrations of citrate-coated titanium...
A bioaccumulation study in red (Palmaria palmata) and green (Ulva sp.) seaweed has been carried out after exposure to different concentrations of citrate-coated titanium dioxide nanoparticles (5 and 25 nm) for 28 days. The concentration of total titanium and the number and size of accumulated nanoparticles in the seaweeds has been determined throughout the study by inductively coupled plasma mass spectrometry (ICP-MS) and single particle-ICP-MS (SP-ICP-MS), respectively. Ammonia was used as a reaction gas to minimize the effect of the interferences in the Ti determination by ICP-MS. Titanium concentrations measured in Ulva sp. were higher than those found in Palmaria palmata for the same exposure conditions. The maximum concentration of titanium (61.96 ± 15.49 μg g) was found in Ulva sp. after 28 days of exposure to 1.0 mg L of 5 nm TiONPs. The concentration and sizes of TiONPs determined by SP-ICP-MS in alkaline seaweed extracts were similar for both seaweeds exposed to 5 and 25 nm TiONPs, which indicates that probably the element is accumulated in Ulva sp. mainly as ionic titanium or nanoparticles smaller than the limit of detection in size (27 nm). The implementation of TiONPs in Ulva sp. was confirmed by electron microscopy (TEM/STEM) in combination with energy dispersive X-Ray analysis (EDX).
Topics: Titanium; Seaweed; Ulva; Mass Spectrometry; Bioaccumulation; Nanoparticles
PubMed: 37420086
DOI: 10.1007/s00604-023-05849-1 -
Biomaterials Oct 1996Although devices made of titanium and its alloy with 6% aluminium and 4% vanadium have been remarkably successful primarily in orthopaedic and dental applications,...
Although devices made of titanium and its alloy with 6% aluminium and 4% vanadium have been remarkably successful primarily in orthopaedic and dental applications, clinical reports have implicated the biological response to released metal from this class of metals as a cause of failure. It is our hypothesis that in the absence of wear, the amount of titanium released is small and will preferentially accumulate in local tissues. One important implication of this is that measurable quantities of titanium in serum and urine that have been observed in clinical studies result from mechanically induced or assisted release phenomena. In order to test this hypothesis, titanium levels in various tissues and fluids of animals both with and without titanium implants need to be determined. In this paper, we report the titanium concentration in serum and urine of rabbits in the absence of wear. Titanium fibre felts were implanted into the tibia of rabbits. At various time points, serum and urine samples were collected from these rabbits as well as from two groups of control rabbits. The samples were analysed for titanium concentration using electrothermal atomic absorption spectrophotometry. The data for the implant group show that titanium levels in serum and urine do not increase in comparison to controls up to one year after implantation. Some clinical studies have documented elevated titanium serum and urine levels in the presence of titanium-based prostheses. The different results from these studies can be resolved by considering titanium release mechanisms other than passive dissolution.
Topics: Analysis of Variance; Animals; Biocompatible Materials; Male; Prostheses and Implants; Rabbits; Surface Properties; Tibia; Titanium
PubMed: 8894084
DOI: 10.1016/0142-9612(96)00023-3