Through the magnifying glass: The effects of size and shape on the uptake, biodistribution and (eco)toxicity of nanoparticles

Although nanoparticles are extensively used in various applications like consumer products and have most probably entered the environment, little is known about the effects of these particles on living organisms. In this thesis, we aim to understand how the size and shape of nanoparticles influence their toxicity. Not only do we compare the toxic effect of these material characteristics over a series of metallic nanoparticles, therewith eliminating the effect of the core-material, but do we also investigate on an individual level where the particles migrate to inside the organism. This thesis aims to obtain a better understanding of the uptake, biodistribution and subsequent toxicity of nanoparticles, moving forward from the “organism as a black box” principle to a more detailed understanding of the harm caused by nanoparticles.Environmental Biolog

Exploring uptake and biodistribution of polystyrene (nano)particles in zebrafish embryos at different developmental stages

Conservation Biolog

Implementing the current knowledge of uptake and effects of nanoparticles in an adverse outcome pathway (AOP) framework

Unlike most other environmental pollution issues, safety assessments of nanoparticles (NPs) were meant to be the prime example on how to foresee and tackle predicted environmental concerns. For once, research efforts were ahead of mass production and potential release into environments. NPs' safety research focuses on the central question of whether the unique properties of NPs cause fundamentally different effects as compared to their larger counterparts. This chapter gives an overview of the present understanding of NP toxicity in aquatic organism. Briefly, state-of-the-art techniques to detect NPs in tissues are summarized and the present understanding of cellular and organismal NP uptake routes given. The location of NPs in tissues bears several challenges but is the first step in identifying target organs or cells and, thus, is important in the search for mechanisms of action. The evaluation of our current knowledge of cellular and organismal responses when exposed to NPs, ultimately, allows for the identification of key knowledge gaps and foresees research directions and the need to develop Adverse Outcome Pathways for NPs.Conservation Biolog

Exploring uptake and biodistribution of polystyrene (nano)particles in zebrafish embryos at different developmental stages.

In ecotoxicology, it is continuously questioned whether (nano)particle exposure results in particle uptake and subsequent biodistribution or if particles adsorb to the epithelial layer only. To contribute to answering this question, we investigated different uptake routes in zebrafish embryos and how they affect particle uptake into organs and within whole organisms. This is addressed by exposing three different life stages of the zebrafish embryo in order to cover the following exposure routes: via chorion and dermal exposure; dermal exposure; oral and dermal exposure. How different nanoparticle sizes affect uptake routes was assessed by using polystyrene particles of 25, 50, 250 and 700nm. In our experimental study, we showed that particle uptake in biota is restricted to oral exposure, whereas the dermal route resulted in adsorption to the epidermis and gills only. Ingestion followed by biodistribution was observed for the tested particles of 25 and 50nm. The particles spread through the body and eventually accumulated in specific organs and tissues such as the eyes. Particles larger than 50nm were predominantly adsorbed onto the intestinal tract and outer epidermis of zebrafish embryos. Embryos exposed to particles via both epidermis and intestine showed highest uptake and eventually accumulated particles in the eye, whereas uptake of particles via the chorion and epidermis resulted in marginal uptake. Organ uptake and internal distribution should be monitored more closely to provide more in depth information of the toxicity of particles

Comparability of behavioural assays using zebrafish larvae to assess neurotoxicity

Testing of compounds for neurotoxicity has become increasingly important in recent years. It has been shown that neurological disorders like autism may be related to chemical exposures, which may play a crucial role in the progression of these diseases. Special attention has been be given to the substances causing developmental neurotoxicity as the developing nervous system is more vulnerable to impacts by chemicals than the adult nervous system. The zebrafish (Danio rerio) is a well-established model species in developmental biology and an emerging model in behavioural and neurological studies. Zebrafish larvae display numerous behavioural patterns highly similar to rodents and humans. Their physical characteristics make them well suited for automated high-throughput screening. In the last years, the number of behavioural studies conducted with zebrafish larvae has increased notably. The goal of this review is to provide an overview of behavioural assays commonly used to test substances for developmental neurotoxicity. Literature from 1995 to 2014 was reviewed and focussed on assays performed with zebrafish larvae younger than 7 days post fertilization (dpf). The behavioural tests were scrutinized, and parameters describing the different experimental setups were defined. In the next step, we investigated if differences in the experimental parameters alter the outcome of the test. In order to test the comparability of behavioural assays, we analysed several studies using ethanol, valproate and pentylenetetrazole as model substances. Based on our findings, we provide recommendations which could help improve future behavioural studies performed with zebrafish larvae

The biodistribution and immuno-responses of differently shaped non-modified gold particles in zebrafish embryos

Biological and Soft Matter Physic

Il MeSH parla anche italiano, Roma 27 Giugno 2006

Report about the meeting “Il MeSH parla anche italiano nella ricerca, l’editoria, la promozione della salute”, held in Rome on the 27 June.Resoconto del convegno “Il MeSH parla anche italiano nella ricerca, l’editoria, la promozione della salute”, tenutosi a Roma il 27 Giugno presso l’Istituto Superiore di Sanità