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The evaluation of engineered nanomaterial safety has been hindered by conflicting reports demonstrating differential degrees of toxicity with the same nanoparticles. The unique properties of these materials increase the likelihood that they will interfere with analytical techniques, which may contribute to this phenomenon. We tested the potential for: 1) nanoparticle intrinsic fluorescence/absorbance, 2) interactions between nanoparticles and assay components, and 3) the effects of adding both nanoparticles and analytes to an assay, to interfere with the accurate assessment of toxicity. Silicon, cadmium selenide, titanium dioxide, and helical rosette nanotubes each affected at least one of the six assays tested, resulting in either substantial over- or under-estimations of toxicity. Simulation of realistic assay conditions revealed that interference could not be predicted solely by interactions between nanoparticles and assay components. Moreover, the nature and degree of interference cannot be predicted solely based on our current understanding of nanomaterial behaviour. A literature survey indicated that ca. 95% of papers from 2010 using biochemical techniques to assess nanotoxicity did not account for potential interference of nanoparticles, and this number had not substantially improved in 2012. We provide guidance on avoiding and/or controlling for such interference to improve the accuracy of nanotoxicity assessments. [ABSTRACT FROM AUTHOR]

Current medically relevant metals for prosthetic reconstructions enjoy a relatively good success rate, but their performance drops significantly in patients with compromised health status, and post-surgical infections still remain an important challenge. To address these problems, different nanotechnology-based strategies have been exploited to create implantable metals with an enhanced bioactivity and antibacterial capacities. Among these, oxidative nanopatterning has emerged as a very effective approach to engender nanoporous surfaces that stimulate and guide the activity of adhering cells. The resulting nanoporosity is also attractive because it offers nanoconfined volumes that can be exploited to load bioactive compounds and modulate their release over time. Such extended elution is needed since a single exposure to growth factors and/or antibiotics, for instance, may not be adequate to further sustain bone regeneration and/or to counteract bacterial colonization. In this article, we assessed the capacities of nanoporous titanium surfaces generated by oxidative nanopatterning to provide controlled and sustained elution of proteins and antibiotic molecules. To this end, we have selected bovine serum albumin (BSA) and vancomycin to reflect commonly used compounds, and investigated their adsorption and elution by Fourier-transform infrared (FT-IR) and ultraviolet–visible (UV-VIS) spectroscopy. Our results demonstrate that while the elution of albumin is not significantly affected by the nanoporosity, in the case of vancomycin, nanoporous surfaces provided an extended release. These findings were successively correlated to the establishment of interactions with the surface and physical-entrapment effects exerted by the nanopores, ultimately highlighting their synergistic contribution to the release profiles and thus their importance in the design of nanostructured eluting platforms for applications in medicine. [ABSTRACT FROM AUTHOR]

We have studied in vitro toxicity of iron oxide nanoparticles (NPs) coated with a thin silica shell (Fe3O4/SiO2 NPs) on A549 and HeLa cells. We compared bare and surface passivated Fe3O4/SiO2 NPs to evaluate the effects of the coating on the particle stability and toxicity. NPs cytotoxicity was investigated by cell viability, membrane integrity, mitochondrial membrane potential (MMP), reactive oxygen species (ROS) assays, and their genotoxicity by comet assay. Our results show that NPs surface passivation reduces the oxidative stress and alteration of iron homeostasis and, consequently, the overall toxicity, despite bare and passivated NPs show similar cell internalization efficiency. We found that the higher toxicity of bare NPs is due to their stronger in-situ degradation, with larger intracellular release of iron ions, as compared to surface passivated NPs. Our results indicate that surface engineering of Fe3O4/SiO2 NPs plays a key role in improving particles stability in biological environments reducing both cytotoxic and genotoxic effects. [ABSTRACT FROM AUTHOR]

Nanostructured three-dimensional constructs combining layer-by-layer technology (LbL) and template leaching were processed and evaluated as possible support structures for cartilage tissue engineering. Multilayered constructs were formed by depositing the polyelectrolytes chitosan (CHT) and chondroitin sulphate (CS) on either bidimensional glass surfaces or 3D packet of paraffin spheres. 2D CHT/CS multi-layered constructs proved to support the attachment and proliferation of bovine chondrocytes (BCH). The technology was transposed to 3D level and CHT/CS multi-layered hierarchical scaffolds were retrieved after paraffin leaching. The obtained nanostructured 3D constructs had a high porosity and water uptake capacity of about 300%. Dynamical mechanical analysis (DMA) showed the viscoelastic nature of the scaffolds. Cellular tests were performed with the culture of BCH and multipotent bone marrow derived stromal cells (hMSCs) up to 21 days in chondrogenic differentiation media. Together with scanning electronic microscopy analysis, viability tests and DNA quantification, our results clearly showed that cells attached, proliferated and were metabolically active over the entire scaffold. Cartilaginous extracellular matrix (ECM) formation was further assessed and results showed that GAG secretion occurred indicating the maintenance of the chondrogenic phenotype and the chondrogenic differentiation of hMSCs. [ABSTRACT FROM AUTHOR]