Projects / Programmes
Elaboration and evaluation of a toxicity test for engineered nanoparticles with terrestrial isopods
| Code |
Science |
Field |
Subfield |
| 1.03.01 |
Natural sciences and mathematics |
Biology |
Zoology and zoophysiology |
| Code |
Science |
Field |
| B361 |
Biomedical sciences |
Physiology of invertebrates |
| B130 |
Biomedical sciences |
Physiological biophysics |
| B740 |
Biomedical sciences |
Pharmacological sciences, pharmacognosy, pharmacy, toxicology |
toxicity testing, nanoparticles, biomarkers, invertebrates, electron microscopy
Researchers (18)
Organisations (4)
Abstract
There are risk issues with every new technology. With the increasing presence of nanomaterials in commercial products, a growing debate is emerging on whether the environmental and social costs of nanotechnology outweigh its many benefits. Information about safety and potential hazards of nano-sized particles is urgently needed. To date, only a few studies have investigated the toxicological effects of nanomaterials and no clear guidelines exist on how to quantify these effects.
In the proposed work we will modify the existing test for soluble chemicals to be applicable for nanomaterials. We plan to develop relevant, robust, reproducible and relatively cheap toxicity tests for engineered nanomaterials with the terrestrial isopod Porcellio scaber (Isopoda, Crustacea). Terrestrial isopods have been well characterised for their relevance in (eco)toxicity studies. In toxicity tests with terrestrial isopods, biomarkers on various levels of biological organization are assessed, and values for effect concentration (EC) or lowest observed effect concentration (LOEC), no observed effect concentration (NOEC) values as well as effect level (EL), lowest observed effect level (LOEL) OR no observed effect level (NOEL) for tested chemicals are generated.
We aim to produce a toxicity test that:
a) Can be used as a screening tool before other laboratory tests (relevant to humans or environment) are selected;
b) Can be used in comparative toxicity studies of nanoparticles and their corresponding bulk material;
c) Can be used as a toxicity test of choice for environmental samples.
Conventional transmission electron microscopy (TEM) and focused ion beam (FIB)/scanning electron microscopy (SEM) will be used to characterise tested nanoparticles. Intracellular distribution of nanoparticles will also be investigated by TEM and FIB/SEM. Results of the project will be published in scientific papers and shared in the Nano Safety Reporting System. With our findings we will participate in risk communication with public at both national and international levels. We believe that the concerns about nanoparticles’ toxicity must be addressed while the field is still young and exposures limited.
Significance for science
The aim of the project was to investigate time- and dose-dependent in vivo effect of ingested nanosized TiO2, nanoZnO, nanoAg and nanoCu. Analysis of the effects of nanoparticles on cell membrane stability, lipid peroxidation and mitochondrial membrane potential on digestive gland cells of the model organism (Porcellio scaber, Isopoda, Crustacea) under realistic in vivo conditions allows identification of interactions between the epithelium of the digestive gland and nanoparticles.
1) The results suggest that ingested nanosized TiO2 affects first the digestive gland cell membrane. Prolonged exposure and higher exposure concentrations caused also intracellular perturbations including oxidative stress. The three measured cytotoxicity responses showed different patterns of dose and time response. Cell membranes are affected by nanosized TiO2 before oxidative stress or metabolic changes are recorded. We observed a threshold response for membrane destabilization. Lipid peroxidation was time-dependent and mitochondrial function was neither time nor dose dependent. Oxidative stress as measured by lipid peroxidation was accompanied by biogenesis of mitochondria and cell membrane destabilization. The in vivo experimental conditions used allow assessment of conventional cytotoxicity biomarkers as a function of exposure to nanoparticles.
2) In case of nanoZnO, nanoAg and nanoCu similar effects were observed, but at the present state of knowledge it is not possible to distinguish the effect of nanoaprticles from the effct of disoluted ions from nanoparticles. For example in case of nanoZnO, nanoCu and nanoAg, dissolution is well documented and the major “nano” effect is actually attributed to these ions and not nanoparticles.
3) The major difference in testing the effects of nanoparticles and soluble chemicals is that nanoparticles must be well characterised. Both, primary characteristics (particle size, crystal structure etc.) must be known as well as secondary characteristics, which depend on the medium, where nanoparticles are suspended (size of aggregates, zeta potential etc.
4) Oxidative stress is involved in a cascade of effects cased by nanoparticles but it is not the initial response. Most probably nanoparticles interact first with cell membrane and subsequently with higher concentration or prolonged exposure other cellular effects occur.
5) A model test organism Porcellio scaber (Isopoda, Crustacea) proved to be well suited to assess biological potential of different nanoparticles.
In our project we succeeded to elaborate a battery of biomarkers, which could substantially help in environmental risk assessment (ERA). The results of our project are most beneficial in environmental hazard characterization and in comparative toxicity studies of chemical pollutants and products of new technologies also in Slovenia.
Significance for the country
To date, few studies have investigated the toxicological and environmental effects of direct and indirect exposure to nanomaterials and no clear guidelines exist to quantify these effects. One reason for that lies in the fact that it is not clear whether the existing methods for toxicity testing are useful also for nanoparticles.
The results of our study answered part of this question and provided a useful tool for nanoparticle risk characterisation that could be used for variety of nanopartilcles.
In our project we succeeded to elaborate a battery of biomarkers, which could substantially help in hazard characterisation of nanoparticles and environmental risk assessment (ERA). The results of our project are most beneficial in environmental hazard characterization and in comparative toxicity studies of chemical pollutants and products of new technologies also in Slovenia.
Most important scientific results
Annual report
2008,
final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
Annual report
2008,
final report,
complete report on dLib.si
