Titanium Accumulation Research Articles

The Acute Liver Injury in Mice Caused by Nano-Anatase TiO2.

Although it is known that nano-TiO2or other nanoparticles can induce liver toxicities, the mechanisms and the molecular pathogenesis are still unclear. In this study, nano-anatase TiO2(5 nm) was injected into the abdominal cavity of ICR mice for consecutive 14 days, and the inflammatory responses of liver of mice was investigated. The results showed the obvious titanium accumulation in liver DNA, histopathological changes and hepatocytes apoptosis of mice liver, and the liver function damaged by higher doses nano-anatase TiO2. The real-time quantitative RT-PCR and ELISA analyses showed that nano-anatase TiO2can significantly alter the mRNA and protein expressions of several inflammatory cytokines, including nucleic factor-κB, macrophage migration inhibitory factor, tumor necrosis factor-α, interleukin-6, interleukin-1β, cross-reaction protein, interleukin-4, and interleukin-10. Our results also implied that the inflammatory responses and liver injury may be involved in nano-anatase TiO2-induced liver toxicity.

Biochemical Toxicity of Nano-anatase TiO2 Particles in Mice

Previous research on the biological and toxic effects of nano-TiO(2) particles on animals only limit to a single dose. However, the toxicity caused by single dose nano-TiO(2) does not truly represent ecological and health effects of nano-TiO(2) retained in the environment. In order to further evaluate the toxicity of nano-TiO(2) particles, nano-anatase TiO(2) (5 nm) was injected into the abdominal cavity of ICR mice everyday for 14 days and the coefficients of organs and serum biochemical parameters were investigated. The results showed that, with increasing doses of nano-anatase TiO(2), the coefficients of liver, kidney, and spleen increased gradually, while the coefficients of lung and brain decreased gradually, and the coefficient of heart had little change. The order of the titanium accumulation in the organs was liver > kidneys > spleen > lung > brain > heart. The serum biochemical parameters with lower dose of nano-anatase TiO(2) showed little difference compared with the control mice, while with higher dose of nano-anatase TiO(2), the indicators of liver function, such as alkaline phosphatase, alanine aminotransferase, leucine acid peptide, pseudocholinesterase, total protein, and albumin level, were enhanced significantly; the indicators of kidney function, such as uric acid and blood urea nitrogen, were decreased; the activities of aspartate aminotransferase, creatine kinase, lactate dehydrogenase, and alpha-hydroxybutyrate dehydrogenase, indicator of the myocardium function, were increased. The contents of triglycerides, glucose, and high-density lipoprotein cholesterol were significantly elevated. Taken together, nano-anatase TiO(2) in higher dose caused serious damage to the liver, kidney, and myocardium of mice and disturbed the balance of blood sugar and lipid in mice. The accumulation of titanium in the organs might be closely related to the coefficients of organs and the inflammatory responses of mice.

Phagocytosis of titanium particles and necrosis in TNF-α-resistant mouse sarcoma L929 cells

In the oral cavity, titanium is an excellent biocompatible material. However, it is reported that high ratios of intracellular titanium particles can cause cell apoptosis or necrosis by as-yet unknown mechanisms. The purpose of this study was to investigate the response of tumor necrosis factor alpha (TNF-α)-resistant L929 fibroblasts to titanium particles. Cells were cultured in Eagle's medium supplemented with fetal bovine serum and l-glutamine. Titanium particle sizes were less than 9 μ. Cytotoxicity was assayed by a cell counting kit, trypan blue dye exclusion test and lactate dehydrogenase (LDH) leakage. The production of reactive oxygen species (ROS) was detected by a confocal laser scanning microscope (CLSM) using dichlorofluorescein diacetate as a fluorescent probe. Morphology was viewed by a CLSM and with an X-ray microanalyser (XMA). When titanium particles were added to cells, the viability decreased to around 50% at a particle concentration of 2.0%. The number of dead cells and LDH activity in the culture media increased significantly between 1 and 2 days. However, formation of active oxygen species did not occur, since no dichlorofluorescein fluorescence was observed. A scanning electron photomicrograph (SEM) revealed a large number of particles covering or adhering to cellular components in lysed cells compared with flattened control cells attached to the substrate. The XMA showed that the titanium accumulation was coincident with the deformed cell shape. The CLSM also confirmed that particles were within the cells. From these results it was concluded that titanium particles ingested in large quantities into the cell induced necrosis by a pathway other than by producing ROS.

Titanium release from dental implants: an in vivo study on sheep

Titanium and its alloys release passive metal dissolution products. This raises the issues of the amount and fate of these products. In this study, we document titanium levels released from dental implants. We compared commercially pure titanium, titanium alloy (Ti6Al4V) and the effect of hydroxyapatite (HA) coating on dental implants. Seventeen screw type implants were inserted into the cortical bone of sheep's tibias. Bone and soft tissues (liver, spleen, kidney, lymph nodes and connective tissues) were harvested. Samples were analyzed for Ti content by proton induced X-ray emission (PIXE). Results from bone were compared with those obtained by the energy-dispersive X-ray analysis (EDX) on scanning electron microscopy (SEM). The results suggest that bone remodeling may reduce the local accumulation of titanium.

Determination of diffusion in polycrystalline platinum thin films

Grain boundary diffusion of titanium through platinum thin films has been carried out in the temperature range from 200 to 600 °C. Five different platinum/titanium bilayer thicknesses, from 35 to 800 Å Pt, were annealed in 5% O2/95% N2. The accumulation of titanium at the platinum surface layer was measured by x-ray photoelectron spectroscopy (XPS) to determine the grain boundary diffusion coefficient (Db). Diffusivity values were calculated based on two different analysis methods assuming type C kinetics. For Pt layers thicker than 200 Å, the activation energy (Qb) for titanium diffusion was found to be 118±15 kJ/mol (1.22±0.16 eV). For Pt layers thinner than 200 Å, there was a thickness dependence on the diffusion kinetics, resulting in activation energies as low as 20±4 kJ/mol (0.21±0.04 eV). XPS results gave no evidence for any Pt-Ti alloy formation in these layers. The suppression of alloy formation may be attributed to the presence of oxygen at the Pt/Ti interface during layer deposition. The quantitative analysis of titanium interdiffusion in platinum provides valuable information regarding Pt/Ti surface concentrations in thin-film chemical sensors, and for understanding changes in operational characteristics of platinum electrodes.

Application of Adsorptive Stripping Voltammetry to the Determination of Trace Levels of Titanium in Mice Organs

Trace levels of titanium (Ti) in mice organs were determined by adsorptive stripping voltammetry (AdSV) using mercury film microelectrodes (MFM). The method is based on the interfacial accumulation of Ti(IV)/mandelic acid complex by absorption at the potential of –0.15 V onto the MFM in the presence of mandelic acid 5.00×10–3 mol/L and potassium chlorate 4.00×10–2 mol/L at pH 3.4–3.5. The dependence of the peak current on different experimental variables is reported. The results achieved by AdSV were compared to those obtained by atomic absorption spectrometry (AAS) to guarantee the accuracy of the electroanalytical method developed. A significant accumulation of titanium was seen in the mice spleen, liver and the kidney under the test conditions described here. The histological studies showed that this metal was relatively well tolerated and did not induce abnormal morphological changes in the cells of the organs studied during the time of study.

Local accumulation of titanium released from a titanium implant in the absence of wear

Titanium and its alloys, like the majority of metallic implant materials, release passive metal dissolution products. This raises the issues of amount and fate, i.e. transport, storage, and/or excretion of these metal dissolution products. In this paper we document titanium levels in tissues local to a commercially pure titanium implant in the absence of wear; compare these values to control tissues; and determine the relative contribution of the local accumulation to total release. Titanium fiber felts were implanted into the tibia of rabbits for periods up to 1 year. Bone and muscle tissue samples near the implant were collected. Using electrothermal atomic absorption spectrophotometry the samples were analyzed for titanium content. Compared to controls, titanium levels in the bone near the implant were elevated at 1-, 4-, and 12-month postoperative time points. The 12-month time point had higher periprosthetic bone titanium levels than both the 1- and the 4-month implant groups. Titanium levels in muscle tissue near the felt also indicated release was occurring. The data support the hypothesis that metal species released from titanium implants in the absence of wear have a limited solubility. As a result, they tend to remain in an area local to the implant. © 1996 John Wiley & Sons, Inc.

Local accumulation of titanium released from a titanium implant in the absence of wear.

Titanium and its alloys, like the majority of metallic implant materials, release passive metal dissolution products. This raises the issues of amount and fate, i.e. transport, storage, and/or excretion of these metal dissolution products. In this paper we document titanium levels in tissues local to a commercially pure titanium implant in the absence of wear; compare these values to control tissues; and determine the relative contribution of the local accumulation to total release. Titanium fiber felts were implanted into the tibia of rabbits for periods up to 1 year. Bone and muscle tissue samples near the implant were collected. Using electrothermal atomic absorption spectrophotometry the samples were analyzed for titanium content. Compared to controls, titanium levels in the bone near the implant were elevated at 1-, 4-, and 12-month postoperative time points. The 12-month time point had higher periprosthetic bone titanium levels than both the 1- and the 4-month implant groups. Titanium levels in muscle tissue near the felt also indicated release was occurring. The data support the hypothesis that metal species released from titanium implants in the absence of wear have a limited solubility. As a result, they tend to remain in an area local to the implant.

PIXE and micro-PIXE studies of ion release around endosseous implants in animals

The so-called “osseointegration” of oral and orthopedic implants means that newly-formed bone embeds the alloplastic implant materials allowing long-term clinical success. Commercially pure smooth titanium, rough titanium (sand blasted or plasma spray coated), hydroxylapatite and other coatings present different patterns, especially in the early healing phase after surgery. PIXE and micro-PIXE analysis are to be considered effective techniques to measure ion diffusion at the implant-bone interface, and to evaluate the possible diffusion of metal into the organism. Investigations were carried out in rabbits, both with PIXE and micro-PIXE, to evaluate a possible release of titanium from implants into the tissues and to measure other elements at the bone-implant border. Preliminary results suggest that a minor diffusion of titanium exists, even if probably without any significant clinical disturbance. Indeed, there is some evidence of initial titanium accumulation in some organs after six months. A possible deposition of calcium and phosphorus on the metal might indicate a good biological behavior of titanium.

Experimental long-term study of titanium ions eluted from pure titanium miniplates.

A long-term study of titanium miniplates, which are in wide clinical use, was conducted to clarify their usefulness as a permanent fixing device. We examined by scanning electron microscopy the surfaces of removed plates and the accumulation of titanium in the organs of Japanese white rabbits. Two years after implantation the titanium plates were only slightly corroded. In addition, marked titanium accumulation was noted in the organs, especially in the lungs. However, the accumulation of titanium in the organs of animals with left distomolar mandibular fracture was highest at 3 months after implantation, and then gradually decreased over 2 years. Titanium miniplates have recently been used clinically in humans and no adverse reactions have yet been reported. The present findings suggest the use of titanium miniplates as permanent fixing devices.

Photocatalytic hydrogen evolution from aqueous Pt/TiO2 suspension in the presence of oxalic acid

Accumulation of titanium (III) oxalate was found to accompany hydrogen evolution upon UV irradiation of aqueous suspensions containing Pt/TiO2 and oxalic acid. The former appears to take part in the process of hydrogen evolution as an electron relay.

A model for diffusion-limited accumulation of iron and titanium in coal liquefaction catalysts

A simple model has been developed to predict the diffusion-limited accumulation of Fe and Ti in coal liquefaction catalysts used in the Wilsonville, AL, two-stage liquefaction (TSL) pilot plant. The model has the form of two ordinary differential equations (ODE's) which can be solved by using a simple finite difference scheme with time stepping. The model is based on a first-order adsorption of contaminant with linear site blocking and subsequent saturation. The Thiele moduli for both contamination processes have been estimated to be in the range 3 - 7. This model was developed after an extensive characterization of fouled catalysts was combined with a series of numerical experiments based on a more general partial differential equation model which included transient behavior and various adsorption and site blocking orders. The results of the model discrimination demonstrate the advantages of using data such as the spatial distribution of contaminants in the process of model development.

An analysis of the element content of lichens from the Northwest Territories, Canada

The results of a survey of the element content of saxicolous and terricolous lichens collected from the Northwest Territories, Canada, are summarized. Fourteen lichen species were collected from 45 sites and the lichens were analysed for 20 elements by instrumental neutron activation and X-ray fluorescence.An enrichment factor (EF) was calculated for each element analysis. The elements aluminium, chromium, iron, sodium, titanium, and vanadium had mean EF values of 1–5 for all species. These low EF values indicated that, relative to average values for crustal rock, there was no enrichment of these elements in the lichens concerned. For other elements (chlorine, lead, and sulphur) consistently higher EF values were obtained. These higher values were interpreted in terms of (a) differing methods of element accumulation, (b) sources of elements both natural and anthropogenic other than crustal rock and (or) soil, and (c) marked deviations of the actual substrate concentrations from the average crustal-rock concentrations used.The underlying structure of the data from some species was investigated using ordination techniques. These techniques provided some description of the element associations within the lichen thallus. These element associations were examined in relation to sources external to the plant. A principal component analysis was carried out on the data for each of three species, Cetraria cucullata, C. nivalis, and Cladina stellaris. In all cases, the first five principal components explained 81–89% of the variation in the data. One component which had high weightings for aluminium, scandium, and vanadium (with or without iron, nickel, and titanium) was common to all three species. Similarly, a second component with high weightings for calcium (with or without magnesium and potassium) was a consistent feature of each analysis. These and other components were considered in the context of lichen enrichment from crust-derived particulates, the marine aerosol, and certain anthropogenic sources. The high percentage of variation explained by the first five components strongly indicated that the major element sources contributing to this variation were considered. Nonmetric multidimensional scaling supported the principal component solution.There was considerable interspecific variation in the element content of the lichens. Univariate analysis of variance did not show any significant differences between the element content of Cladina arbuscula, C. rangiferina, and C. stellaris or any differences between Cetraria cucullata and C. nivalis on the basis of any single element. However, multiple discriminant analysis did show that the species mentioned could be distinguished (~ 90% discrimination) when all the elements were compared simultaneously. The discrimination between the Cladina spp. was based on the relative efficiency of these lichens in the accumulation of iron, scandium, titanium, and vanadium.