Development of novel osteochondral scaffolds and relatedenvironment with the aid of chemical engineering principles.

In tissue engineering, collaboration among experts from different fields is needed to design appropriate cell scaffolds and the required three-dimensional environment. Osteochondral tissue engineering is particularly challenging due to the need to provide scaffolds that imitate structural and compositional differences between two neighboring tissues, articular cartilage and bone, and the required complex biophysical environments for cultivating such scaffolds. This work focuses on two key objectives: first, to develop bilayered osteochondral scaffolds based on gellan gum and bioactive glass and, second, to create a biomimetic environment for scaffold characterization by designing and utilizing novel dual-medium cultivation bioreactor chambers.

The Relevance of Physico-Chemical Properties and Protein Corona for Evaluation of Nanoparticles Immunotoxicity-In Vitro Correlation Analysis on THP-1 Macrophages.

Alongside physiochemical properties (PCP), it has been suggested that the protein corona of nanoparticles (NPs) plays a crucial role in the response of immune cells to NPs. However, due to the great variety of NPs, target cells, and exposure protocols, there is still no clear relationship between PCP, protein corona composition, and the immunotoxicity of NPs. In this study, we correlated PCP and the protein corona composition of NPs to the THP-1 macrophage response, focusing on selected toxicological endpoints: cell viability, reactive oxygen species (ROS), and cytokine secretion.

Silk fibroin induces chondrogenic differentiation of canine adipose-derived multipotent mesenchymal stromal cells/mesenchymal stem cells.

Under appropriate culture conditions, mesenchymal stem cells (MSC), also called more properly multipotent mesenchymal stromal cells (MMSC), can be induced toward differentiation into different cell lineages. In order to guide stem cell fate within an environment resembling the stem cell niche, different biomaterials are being developed. In the present study, we used silk fibroin (SF) as a biomaterial supporting the growth of MMSC and studied its effect on chondrogenesis of canine adipose-derived MMSC (cADMMSC).

Viscoelastic behaviour of hydrogel-based composites for tissue engineering under mechanical load.

Along with biocompatibility, bioinductivity and appropriate biodegradation, mechanical properties are also of crucial importance for tissue engineering scaffolds. Hydrogels, such as gellan gum (GG), are usually soft materials, which may benefit from the incorporation of inorganic particles, e.g.

Characterisation of food contact non-stick coatings containing TiO nanoparticles and study of their possible release into food.

Novel nanoparticles containing non-stick coatings have been developed for food contact applications such as frying pans. Possible release of nanoparticles from such coatings into food is not known. In this paper, the characterisation of commercially available non-stick coatings was performed by use of FTIR, electron and optical microscopy, EDXS and XRD analysis.

Electrokinetic behaviour of porous TiO2-coated implants.

It is known that the "race for the surface" determining the in vivo response is strictly connected to the physico-chemical properties of the material, especially at its surface. Accordingly, the study of surface roughness, charge and wettability is fundamental to predict the bio-response to the implant. In this work, streaming potential was chosen as a reliable method to quantify the solid surface charge of hydrothermally treated (HT) TiO2-anatase nano-crystalline coatings, grown on titanium substrates.

Enhanced osteogenesis on titanium implants by UVB photofunctionalization of hydrothermally grown TiO₂ coatings.

Even though Ti-based implants are the most used materials for hard tissue replacement, they may present lack of osseointegration on the long term, due to their inertness. Hydrothermal treatment (HT) is a useful technique for the synthesis of firmly attached, highly crystalline coatings made of anatase titanium dioxide (TiO2), providing favorable nanoroughness and higher exposed surface area, as well as greater hydrophilicity, compared to the native amorphous oxide on pristine titanium. The hydrophilicity drops even more by photofunctionalization of the nanostructured TiO2-anatase coatings under UV light.

The influence of surface modification on bacterial adhesion to titanium-based substrates.

This study examines bacterial adhesion on titanium-substrates used for bone implants. Adhesion is the most critical phase of bacterial colonization on medical devices. The surface of titanium was modified by hydrothermal treatment (HT) to synthesize nanostructured TiO2-anatase coatings, which were previously proven to improve corrosion resistance, affect the plasma protein adsorption, and enhance osteogenesis.

Nanoparticulate bioactive-glass-reinforced gellan-gum hydrogels for bone-tissue engineering.

This work presents bioactive-glass-reinforced gellan-gum spongy-like hydrogels (GG-BAG) as novel hydrophilic materials for use as the scaffolding in bone-tissue engineering. The reinforcement with bioactive-glass particles resulted in an improvement to the microstructure and to the mechanical properties of the material. These mechanical properties were found to be dependent on the composition and improved with the amount of bioactive glass; however, values necessary to accommodate biomechanical loading were not achieved in this study.

Photoinduced properties of nanocrystalline TiO2-anatase coating on Ti-based bone implants.

The paper reports on the photoinduced properties of hydrothermally treated (HT) titanium used for bone implants. The anatase coatings composed of 30-100nm anatase crystals exhibited high photocatalytic activity and good photo-induced wettability, reaching a superhydrophilic state, despite the larger crystal dimensions than the previously reported optimal ones. These properties are due to a suitable combination of surface texture, roughness, thickness, crystal morphology and particle size, which allowed the two independent photo-induced phenomena to occur simultaneously.

Improvement to the Corrosion Resistance of Ti-Based Implants Using Hydrothermally Synthesized Nanostructured Anatase Coatings.

The electrochemical behavior of polycrystalline TiO₂ anatase coatings prepared by a one-step hydrothermal synthesis on commercially pure (CP) Ti grade 2 and a Ti13Nb13Zr alloy for bone implants was investigated in Hank's solution at 37.5 °C. The aim was to verify to what extent the -grown anatase improved the behavior of the substrate in comparison to the bare substrates.

Analytical electron microscopy of W-core β-SiC fibers for use in an SiC-based composite material for fusion applications.

In this work, the interactions between tungsten (W) and silicon carbide (SiC) in Sigma SiC fibers at high temperatures were characterized using scanning and transmission electron microscopy. These fibers could have the potential for use in fusion-related applications owing to their high thermal conductivity compared with pure SiC-based fibers. The as-received fibers were composed of a 100-μm-thick shell of radially textured β-SiC grains and a 15-μm-thick tungsten core, composed of a few hundreds of nm-sized elongated tungsten grains.

SiC-CNT composite prepared by electrophoretic codeposition and the polymer infiltration and pyrolysis process.

The paper reports on the successful anodic codeposition of submicrometer SiC powder and multiwalled carbon nanotubes from aqueous suspensions to form SiC-CNT composites. On the basis of the comprehensive analysis of the aqueous suspensions with different pHs, solids contents, and CNT contents, optimal conditions for deposition were determined. Besides having the necessary high absolute value of the ζ-potential, the suspensions that resulted in firm deposits were characterized by limited conductivity (<1 mS/cm).

Titanium dioxide in our everyday life; is it safe?

Background: Titanium dioxide (TiO(2)) is considered as an inert and safe material and has been used in many applications for decades. However, with the development of nanotechnologies TiO(2) nanoparticles, with numerous novel and useful properties, are increasingly manufactured and used. Therefore increased human and environmental exposure can be expected, which has put TiO(2) nanoparticles under toxicological scrutiny.

Bioactive glass enhances bone ingrowth into the porous titanium coating on orthopaedic implants.

Purpose: The aim of the study was to verify the ability of nanoparticulate bioactive glass (BAG) to infiltrate into the porous titanium (Ti) layer on Ti-based implants to promote osseointegration.

Methods: The porous titanium layer on Ti-based implants was impregnated with nanoparticulate BAG. The implants without or with BAG were implanted bilaterally in tibial holes of ten New Zealand white rabbits.

Pre-irradiation of anatase TiO2 particles with UV enhances their cytotoxic and genotoxic potential in human hepatoma HepG2 cells.

Titanium dioxide (TiO(2)) is active in the UV region of the light spectra and is used as a photocatalyst in numerous applications. Photo-activated anatase TiO(2) particles promote increased production of free radicals. This is a desirable property, although the potential toxicity of such photo-activated TiO(2) particles on exposure of humans and the environment remains unknown.

DNA damage and alterations in expression of DNA damage responsive genes induced by TiO2 nanoparticles in human hepatoma HepG2 cells.

We investigated the genotoxic responses to two types of TiO2 nanoparticles (<25 nm anatase: TiO(2)-An, and <100 nm rutile: TiO2-Ru) in human hepatoma HepG2 cells. Under the applied exposure conditions the particles were agglomerated or aggregated with the size of agglomerates and aggregates in the micrometer range, and were not cytotoxic. TiO2-An, but not TiO2-Ru, caused a persistent increase in DNA strand breaks (comet assay) and oxidized purines (Fpg-comet).

[Topographic localization of an intraocular foreign body by B-scan echography].

Background/aim: In cases of blurred optic media the ultrasound diagnostics offers useful data about eventual presence of intraocular foreign body as well as about its precise localization in the eye. The aim of this study was to retrospectively analyze echographic findings in patients with the diagnosis of intraocular foreign body with a special interest in localizations of a intraocular foreign body in the eye and the presence of an eventual infection - endophthalmitis. The aim of this study was also to confirm the localization of intraocular foreign body by echography and to test the precision of this method.

Electron microscopy and microanalysis of the fiber-matrix interface in monolithic silicone carbide-based ceramic composite material for use in a fusion reactor application.

A composite material made from continuous monolithic silicone carbide (SiC) fibers and a SiC-based matrix (SiC(f)/SiC), was prepared using a novel technique, i.e. adapted dip coating and infiltration of SiC fibers with a water suspension containing SiC particles and a sintering additive.