Year: 2014
Type: dissertation
Abstract: Engineered nanomaterials (ENM) are widely used in the industry as their unique characteristics improve competitiveness and potential for innovations in the different sectors of industry: It has been estimated that the market size of nanotechnological innovations will exceed 2 trillion euros in 2015. However, the toxicological hazard and risk assessment of different nanomaterials is far from complete. There is a concern that nanomaterials cause toxic outcomes, and more research efforts are put into hazard assessment of nanomaterials. However, the huge amount of differently modified nanomaterials poses a challenge for toxicologists who will have to develop new, quicker and cheaper, approaches for hazard and risk assessment to guarantee the human health. The human body is protected from foreign material by its immune system. The most common routes for foreign materials to enter the human body are via inhalation, digestion or dermal penetration, and these routes are protected by physical barrier. The physical barrier accompanied with phagocytosing cells are part of the innate immunity: Rapid and non-specific immune system. Phagocytosing cells scavenge foreign material in the body cavities and secrete signaling molecules to further activate other cells of immunity, such as T or B cells, to form a specific immune response. In this thesis, an immunotoxicological approach was used to compare effects of different types of ENM in the phagocytosing cells or in the disease model of atopic dermatitis. Studies performed with metal oxide nanoparticles and carbon nanotubes (CNT) showed that surface treatment or shape of nanomaterial modify their toxic properties in vitro. Mechanistical studies performed with CNT clearly demonstrated that long, rigid carbon nanotubes resemble asbestos fibers in their toxicity whereas other types of CNT showed less toxicity. In addition, the effects of either bulk-sized or nano-sized ZnO particles commonly used in cosmetics were compared in the mouse atopic dermatitis disease model. The results clearly showed that ZnO particles were able to suppress local inflammation, however, there was also an induction of systemic antibody levels. These outcomes were clearly higher if the mice skin had been treated with nano-ZnO shown also to penetrate into the deeper layers on mouse allergic skin. The results suggest that material size, shape and surface modifications are important parameters in their toxicity. Therefore the risk assessment of differently modified nanomaterials shall be performed separately despite the previously performed risk assessment of the bulk-sized form of the same material. These results also underline factors that should be taken into account in the planning of the future studies.
Source: Työväentutkimus Vuosikirja
Author: Jaana Palomäki
Language: English
Subfield: Immunology
Field: Immunology and Microbiology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W1525806168