Synthetic polymer nanoparticles: effects of composition and size on uptake, toxicity and interactions with environmental contaminants.

There is considerable public concern about the potential environmental impacts of manufactured nanoparticles (usually interpreted as particles smaller than 100 nm). There are a growing number of studies demonstrating that nanoparticles can be taken up by orgnisms, and can produce negative effects at a cellular level and can be acutely toxic. However, many nanoparticles are poorly characterised, and it is difficult to draw generalisations from these studies. In some cases it is even diffiuclt to know whether the observed toxicity is a direct result of the nanoparticles or is an artefact of the way that toxicity tests are carried out. We urgently need a set of well characterised, standardised particles which differ in particle size and chemical composition so that we can systematically examine the effects of thes particle characteristics on their biological effects. This proposal will take an important step towards the provision of a set of well characterised particles by using methods that are in routine use in our laboratory to make nanoparticles of three different sizes and three different chemical compositions. We will determine the toxicity of these particles to a fungus, an aquatic alga and a freshwater invertebrate, examine whether the particles are taken up by these organisms and determine how particle size and surface chemistry alter uptake and toxicity. We will also examine whether the particles increase or decrease the toxic effects of three common pollutants. The results will allow us to start drawing generalisations about the likely environmental impacts of nanoparticles and the ways that the physical and chemical characteristics of the particles alter their biological effects.