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Query: KEGG:D01931 (TiO2)
 11,320 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The biocompatibility of titania/hydroxyapatite (TiO2 /HA) composite coatings, at different ratio obtained by sol-gel process, were investigated studying the behaviour of human MG63 osteoblast-like cells. The biocompatibility was evaluated by means of cytotoxicity and cytocompatibility tests. Cytotoxicity tests, i.e., neutral red (NR), MTT and kenacid blue (KB) assays, were performed to assess the influence of the material extracts on lysosomes, mitochondria and cell proliferation, respectively. Cell proliferation, some preliminary indications of cell morphology, alkaline phosphatase activity, collagen and osteocalcin production of MG63 cells, cultured directly onto TiO2/HA substrates, were evaluated. The results showed that these materials have no toxic effects. Cell growth and morphology were similar on all the materials tested: on the contrary, alkaline-phosphatase-specific activity and collagen production of osteoblasts cultured on TiO2/HA coatings were significantly higher than uncoated titanium and polystyrene of culture plate and were influenced by chemical composition of the coatings. In particular, TiO2/HA coating at 1:1 ratio (w/w) seems to stimulate more than others the expression of some differentiation markers of osteoblastic phenotype. TiO2/HA coatings resulted to be bioactive owing to the presence of hydroxyl groups detected on their surface that promote the calcium and phosphate precipitation and improve the interactions with osteoblastic cells.
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PMID:The influence of titania/hydroxyapatite composite coatings on in vitro osteoblasts behaviour. 1137 45

Surface oxide properties are regarded to be of great importance in establishing successful osseointegration of titanium implants. Despite a large number of theoretical questions on the precise role of oxide properties of titanium implants, current knowledge obtained from in vivo studies is lacking. The present study is designed to address two aspects. The first is to verify whether oxide properties of titanium implants indeed influence the in vivo bone tissue responses. The second, is to investigate what oxide properties underline such bone tissue responses. For these purposes, screw-shaped/turned implants have been prepared by electrochemical oxidation methods, resulting in a wide range of oxide properties in terms of: (i) oxide thickness ranging from 200 to 1000 nm, (ii) the surface morphology of barrier and porous oxide film structures, (iii) micro pore configuration - pore sizes<8 microm by length, about 1.27 microm2 to 2.1 microm2 by area and porosity of about 12.7-24.4%, (iv) the crystal structures of amorphous, anatase and mixtures of anatase and rutile type, (v) the chemical compositions of TiO2 and finally, (vi) surface roughness of 0.96-1.03 microm (Sa). These implant oxide properties were divided into test implant samples of Group II, III, IV and V. Control samples (Group I) were turned commercially pure titanium implants. Quantitative bone tissue responses were evaluated biomechanically by resonance frequency analysis (RFA) and removal torque (RT) test. Quantitative histomorphometric analyses and qualitative enzyme histochemical detection of alkaline (ALP) and acidic phosphatase (ACP) activities were investigated on cut and ground sections after six weeks of implant insertion in rabbit tibia. In essence, from the biomechanical and quantitative histomorphometric measurements we concluded that oxide properties of titanium implants, i.e. the oxide thickness, the microporous structure, and the crystallinity significantly influence the bone tissue response. At this stage, however, it is not clear whether oxide properties influence the bone tissue response separately or synergistically.
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PMID:Oxidized implants and their influence on the bone response. 1534 59

Inositol phosphates are a large and diverse family of signalling molecules. While genetic studies have discovered important functions for them, the biochemistry behind these roles is often not fully characterized. A key obstacle in inositol phosphate research in mammalian cells has been the lack of straightforward techniques for their purification and analysis. Here we describe the ability of titanium dioxide (TiO2) beads to bind inositol phosphates. This discovery allowed the development of a new purification protocol that, coupled with gel analysis, permitted easy identification and quantification of InsP6 (phytate), its pyrophosphate derivatives InsP7 and InsP8, and the nucleotides ATP and GTP from cell or tissue extracts. Using this approach, InsP6, InsP7 and InsP8 were visualized in Dictyostelium extracts and a variety of mammalian cell lines and tissues, and the effects of metabolic perturbation on these were explored. TiO2 bead purification also enabled us to quantify InsP6 in human plasma and urine, which led to two distinct but related observations. Firstly, there is an active InsP6 phosphatase in human plasma, and secondly, InsP6 is undetectable in either fluid. These observations seriously question reports that InsP6 is present in human biofluids and the advisability of using InsP6 as a dietary supplement.
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PMID:A novel method for the purification of inositol phosphates from biological samples reveals that no phytate is present in human plasma or urine. 2658 73

Enhancing vitamin D-induced human osteoblast (hOB) maturation at bone biomaterial surfaces is likely to improve prosthesis integration with resultant reductions in the need for revision arthroplasty consequent to aseptic loosening. Biomaterials that are less appealing to microorganisms implicated in implant failures through infection are also highly desirable. However, finding surfaces that enhance hOB maturation to active vitamin D yet deter bacteria remain elusive. In addressing this, we have sought to bio-functionalise titanium (Ti) with lysophosphatidic acid (LPA) and related, phosphatase-resistant, LPA analogues. The impetus for this follows our discovery that LPA co-operates with active vitamin D3 metabolites to secure hOB maturation in vitro including cells grown upon Ti. LPA has also been found, by others, to inhibit virulence factor production and biofilm formation of the human opportunistic pathogen Pseudomonas aeruginosa. Collectively, selected LPA species might offer potential dual-action surface finishes for contemporary bone biomaterials. In attaching a phosphatase-resistant LPA analogue to Ti we took advantage of the affinity of alkane phosphonic acids for TiO2. Herein, we provide evidence for the facile development of a dual-action Ti surface for potential orthopaedic and dental applications. Successful conjugation of an LPA analogue (3S)1-fluoro-3-hydroxy-4-(oleoyloxy)butyl-1-phosphonate (FHBP) to the Ti surface was supported through physiochemical characterisation using x-ray photoelectron spectroscopy and secondary ion mass spectrometry. hOB maturation to active vitamin D3 was enhanced for cells grown on FHBP-Ti whilst these same surfaces exhibited clear antiadherent properties towards a clinical isolate of Staphylococcus aureus.
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PMID:Fluorophosphonate-functionalised titanium via a pre-adsorbed alkane phosphonic acid: a novel dual action surface finish for bone regenerative applications. 2670 53