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A unifying review of bioassay-guided fractionation, effect-directed analysis and related techniques
(2012)
The success of modern methods in analytical chemistry sometimes obscures the problem that the ever increasing amount of analytical data does not necessarily give more insight of practical relevance. As alternative approaches, toxicity- and bioactivity-based assays can deliver valuable information about biological effects of complex materials in humans, other species or even ecosystems. However, the observed effects often cannot be clearly assigned to specific chemical compounds. In these cases, the establishment of an unambiguous cause-effect relationship is not possible. Effect-directed analysis tries to interconnect instrumental analytical techniques with a biological/biochemical entity, which identifies or isolates substances of biological relevance. Successful application has been demonstrated in many fields, either as proof-of-principle studies or even for complex samples. This review discusses the different approaches, advantages and limitations and finally shows some practical examples. The broad emergence of effect-directed analytical concepts might lead to a true paradigm shift in analytical chemistry, away from ever growing lists of chemical compounds. The connection of biological effects with the identification and quantification of molecular entities leads to relevant answers to many real life questions.
Due to their unique optical properties, quantum dots (QDs) are used in a number of optoelectronic devices and are forecasted to be used in the near future for biomedical applications. The most popular QD composition consists of cadmium selenide (CdSe) or cadmium telluride (CdTe), which has been shown to pose health risks due to the release of toxic cadmium (Cd) ions. Due to similar optical properties but lower intrinsic toxicity, indium phosphide (InP) QDs have been proposed as a safer alternative. Nevertheless, investigations regarding their safety and possible toxicological effects are still in their infancy.
The fate and toxicity of seven different water-dispersible indium (In) based QDs, either pristine or after ageing in a climatic chamber, was evaluated. The core of these QDs was composed of indium, zinc and phosphorus (InZnP) or indium, zinc, phosphorus and sulfur (InZnPS). They were assessed either as core-only or as core-shell QDs, for which the core was capped with a shell of zinc, selenium and sulfur (Zn(Se,S)). Their Surface was functionalized using either penicillamine or glutathione.
In their pristine form, these QDs showed essentially no cytotoxicity. The particular case of InZnPS QD showed that core-shell QDs were less cytotoxic than core-only QDs. Moreover, surface functionalization with either penicillamine or glutathione did not appreciably influence cytotoxicity but affected QD stability. These QDs did not lead to over-accumulation of reactive oxygen species in exposed cells, or to any oxidative damage to cellular DNA. However, accelerated weathering in a climatic chamber led to QD precipitation and degradation, together with significant cytotoxic effects. Ageing led to dissociation of IneP and ZneS bonds, and to complexation of In Zn ions with carboxylate and/or phosphate moieties.
These results show that InZnP and InZnPS alloyed QDs are safer alternatives to CdSe QDs. They underline the necessity to preserve as much as possible the structural integrity of QDs, for instance by developing more robust shells, in order to ensure their safety for future applications.
JATROPHA - The Seed of Energy - CO2-Neutral Fuels and Lubricants Based on Sustainable Non-Food Oils
(2009)
Cellular effects of Al-, Ti- and Zn-containing nanomaterials on intestinal cell lines in vitro
(2016)
Aluminium-, titanium- and zinc-containing chemicals are highly abundant in food, food contact materials and consumer products. Physical and chemical conversion might lead to a certain amount of nanoscaled particles that can be taken up by the gastrointestinal tract. Nanospecific effects such as higher reactivity, increased surface or altered uptake can increase hazardous potential for human health. The aim of this study as part of the european SolNanoTOX project is to characterize toxicological effects of Al-, Zn- and Ti-containing nanomaterials on intestinal cell lines.
While toxicological potential of zinc species has been well studied, little is known about the effects of aluminium- and titanium-species. We have performed toxicological experiments on the human intestinal cell line Caco-2 for numerous endpoints: Cellular ATP and glutathione levels, apoptosis, necrosis, vesicular uptake, oxidative stress, growth rate and cell cycle modification. While zinc-containing controls showed toxic responses, our utilized aluminium- (elementary Al, γ-Al2O3) and titanium-species (TiO2, rutile) did not. Nevertheless, we detected some differences between both different aluminium nanoparticle species and aluminium ions with regard to cell viability. We also provide strong evidence for particle-specific uptake of aluminium and titanium in the intestinal cell line Caco-2.
In summary, among the different tested endpoints, Al- and Ti-containing nanomaterials did not show any toxicity in intestinal cell lines in vitro. Nevertheless, this absence of effect was not due to an absence of exposure, since particle-specific uptake was reported. Metal particle uptake over a long time might therefore be relevant for risk assessment of aluminium- and titanium-containing food products.
The overall interest in nanotoxicity, triggered by the increasing use of nanomaterials in the material and life sciences, and the synthesis of an ever increasing number of new functional nanoparticles calls for standardized test procedures1,2 and for efficient approaches to screen the potential genotoxicity of these materials. Aiming at the development of fast and easy to use, automated microscopic methods for the determination of the genotoxicity of different types of nanoparticles, we assess the potential of the fluorometric γH2AX assay for this purpose. This assay, which can be run on an automated microscopic detection system, relies on the detection of DNA double strand breaks as a sign for genotoxicity3. Here, we provide first results obtained with broadly used nanomaterials like CdSe/CdS and InP/ZnS quantum dots as well as iron oxide, gold, and polymer particles of different surface chemistry with previously tested colloidal stability and different cell lines like Hep-2 and 8E11 cells, which reveal a dependence of the genotoxicity on the chemical composition as well as the surface chemistry of these nanomaterials. These studies will be also used to establish nanomaterials as positive and negative genotoxicity controls or standards for assay performance validation for users of this fluorometric genotoxicity assay. In the future, after proper validation, this microscopic platform technology will be expanded to other typical toxicity assays.
Vehicle fires in tunnels can have catastrophic consequences for the road users, the property and traffic inffastructure. To support an evacuation planning, this study simulates the fire smoke toxicity and the smoke layer of a vehicle fire in a full-size test tunnel. The three dimensional prediction of the fire smoke toxicity in the test tunnel is realized by implementing the Fractional Effective Dose and the Fractional Summation concept in a CFD environment. The developed model facilitates to calculate fire scenarios for various types of tunnels and to quantify the hazard e.g. during an evacuation scenario.
There are significant differences in toxicity of PM components and cellular responses that can be linked to adverse health effects. Soot and copper oxide induced toxicity, reduced metabolic activity, increased ROS and altered immune response. Increased ROS generation and mitochondrial dysfunctions are well known features in COPD pathology. Toxicity of individual airborne particles can be used to better understand adverse health effects and improve air quality guidelines.
Flame retardants (FR) are inevitable additives to many plastics. Halogenated organics are effective FRs but are controversially discussed due to the release of toxic gases during a fire or their persistence if landfilled. Phosphorus-containing compounds are effective alternatives to halogenated FRs and have potential lower toxicity and degradability. In addition, nitrogencontaining additives were reported to induce synergistic effects with phosphorus-based FRs. However, no systematic study of the gradual variation on a single phosphorus FR containing both P−O and P−N moieties and their comparison to the respective blends of phosphates and phosphoramides was reported. This study developed general design principles for P−O- and P−N-based FRs and will help to design effective FRs for various polymers. We synthesized a library of phosphorus FRs that only differ in their P-binding pattern from each other and studied their decomposition mechanism in epoxy resins. Systematic control over the decomposition pathways of phosphate (PO(OR)3), phosphoramidate (PO(OR)2(NHR)), phosphorodiamidate (PO(OR)(NHR)2), phosphoramide (PO(NHR)3), and their blends was identified, for example, by reducing cis-elimination and the formation of P−N-rich char with increasing nitrogen content in the P-binding sphere. Our FR epoxy resins can compete with commercial FRs in most cases, but we proved that the blending of esters and amides outperformed the single molecule amidates/diamidates due to distinctively different decomposition mechanisms acting synergistically when blended.
Development and market introduction of new nanomaterials trigger the need for an adequate risk assessment of such products alongside suitable risk communication measures. Current application of classical and new nanomaterials is analyzed in context of regulatory requirements and standardization for chemicals, food and consumer products. The challenges of nanomaterial characterization as the main bottleneck of risk assessment and regulation are presented. In some areas, e.g., quantification of nanomaterials within complex matrices, the establishment and adaptation of analytical techniques such as laser ablation inductively coupled plasma mass spectrometry and others are potentially suited to meet the requirements. As an example, we here provide an approach for the reliable characterization of human exposure to nanomaterials resulting from food packaging. Furthermore, results of nanomaterial toxicity and ecotoxicity testing are discussed, with concluding key criteria such as solubility and fiber rigidity as important parameters to be considered in material development and regulation. Although an analysis of the public opinion has revealed a distinguished rating depending on the particular field of application, a rather positive perception of nanotechnology could be ascertained for the German public in general. An improvement of material characterization in both toxicological testing as well as end-product control was concluded as being the main obstacle to ensure not only safe use of materials, but also wide acceptance of this and any novel technology in the general public.
Microplastics are small plastic fragments that are widely distributed in marine and terrestrial environments. While the soil ecosystem represents a large reservoir for plastic, research so far has focused mainly on the impact on aquatic ecosystems and there is a lack of information on the potentially adverse effects of microplastics on soil biota. Earthworms are key organisms of the soil ecosystem and are due to their crucial role in soil quality and fertility a suitable and popular model organism in soil ecotoxicology.
Therefore, the aim of this study was to gain insight into the effects of environmentally relevant concentrations of microplastics on the earthworm Eisenia andrei on multiple levels of biological organization after different exposure periods. Earthworms were exposed to two types of microplastics: (1) polystyrene-HBCD and (2) car tire abrasion in natural soil for 2, 7, 14 and 28 d. Acute and chronic toxicity and all subcellular investigations were conducted for all exposure times, avoidance behavior assessed after 48 h and reproduction after 28 d. Subcellular endpoints included enzymatic biomarker responses, namely, carboxylesterase, glutathione peroxidase, acetylcholinesterase, glutathione reductase, glutathione S-transferase and catalase activities, as well as fluorescence-based measurements of oxidative stress-related markers and multixenobiotic resistance activity. Multiple biomarkers showed significant changes in activity, but a recovery of most enzymatic activities could be observed after 28 d. Overall, only minor effects could be observed on a subcellular level, showing that in this exposure scenario with environmentally relevant concentrations based on German pollution levels the threat to soil biota is minimal. However, in areas with higher concentrations of microplastics in the environment, these results can be interpreted as an early warning signal for more adverse effects. In conclusion, these findings provide new insights regarding the ecotoxicological effects of environmentally relevant concentrations of microplastics on soil organisms.