Comparison of Metal-Based Nanoparticles and Nanowires: Solubility, Reactivity, Bioavailability and Cellular Toxicity

While the toxicity of metal-based nanoparticles (NP) has been investigated in an increasing number of studies, little is known about metal-based fibrous materials, so-called nanowires (NWs). Within the present study, the physico-chemical properties of particulate and fibrous nanomaterials based on Cu, CuO, Ni, and Ag as well as TiO2 and CeO2 NP were characterized and compared with respect to abiotic metal ion release in different physiologically relevant media as well as acellular reactivity. While none of the materials was soluble at neutral pH in artificial alveolar fluid (AAF), Cu, CuO, and Ni-based materials displayed distinct dissolution under the acidic conditions found in artificial lysosomal fluids (ALF and PSF). Subsequently, four different cell lines were applied to compare cytotoxicity as well as intracellular metal ion release in the cytoplasm and nucleus. Both cytotoxicity and bioavailability reflected the acellular dissolution rates in physiological lysosomal media (pH 4.5); only Ag-based materials showed no or very low acellular solubility, but pronounced intracellular bioavailability and cytotoxicity, leading to particularly high concentrations in the nucleus. In conclusion, in spite of some quantitative differences, the intracellular bioavailability as well as toxicity is mostly driven by the respective metal and is less modulated by the shape of the respective NP or NW.

Biokinetic Evaluation of Contrast Media Loaded Carbon Nanotubes Using a Radiographic Device

Considerable progress has been made in various fields of applied research on the use of carbon nanotubes (CNTs). Because CNTs are fibrous nanomaterials, biosafety of CNTs has been discussed. The biokinetic data of CNTs, such as using the radioisotope of carbon and surface labeling of CNTs, have been reported. However, the use of radioisotopes requires a special facility. In addition, there are problems in the surface labeling of CNTs, including changes in surface properties and labels eliminating over time. In order to solve these problems and properly evaluate the biokinetics of CNTs, the authors synthesize peapods with platinum (Pt) encapsulated within the hollow region of Double-Walled CNTs (DWCNTs) and develop a new system to evaluate biokinetics using widely available imaging equipment. In the cell assay, no significant difference is observed with and without Pt in CNTs. In animal studies, radiography of the lungs of rats that inhaled Pt-peapods show the detectability of Pt inside the CNTs. This new method using Pt-peapods enables image evaluation with a standard radiographic imaging device without changing the surface property of the CNTs and is effective for biokinetics evaluation of CNTs.

Effect of Gamma-Irradiation on Properties of Polymer/Fibrous/Nanomaterials Particleboard Composites

This investigation aimed to study the role of different contents of nano-slag, as well as various doses of gamma-irradiation on physical and mechanical properties of rice husk-polyvinyl chloride particleboard composites. Equal proportions of rice husk fibers and polyvinyl chloride polymer were used. The treatment of rice husk fibers with silane coupling agent showed a significant improvement in both mechanical and physical properties of the prepared particleboard composites as compared to those containing untreated rice husk fibers. Moreover, the partial replacement of polyvinyl chloride with different percentages of nano-slag namely 5, 10, 15, and 20% by the weight of polymer manifested a good effect on the properties of the resulting particleboard composites precisely at 10%nano-slag. In addition, the effect of different gamma-irradiation doses on the properties of the particleboard composite specimens that contain 10% nano-slag showed an enhancement in the physical (thickness swelling %) and mechanical (flexural strength, and hardness) properties. In addition, the results elaborated that the irradiated particleboard composites had a good thermal stability.