Project Background
Indications of the potential toxicity of engineered nanoparticles can be drawn from epidemiological studies of inhaled environmental particulate matter in humans.These show that one of the primary target organs, in this case the lung, cannot necessarily defend other body systems from the effects of inhaling very small, ultrafine, nanosized material. Consequently, the cardiovasculature is also affected. Clues from these human studies suggested the possibility that particles may enter the circulation and translocate to other organs and/or that there are “knock-on” systemic effects due to locally produced pro-inflammatory and pro-thrombotic mediators. Clearly, other mechanisms may exist. Studies in experimental animals suggest that inhaled nano-sized particles relocate to the brain, vasculature, liver, kidneyand spleen. Similarly, intravenous nanoparticles can access multiple organs including the foetus. Other important portals of entry of exogenous nano-substances are the skin and gastrointestinal tract. Furthermore, there is in vivo evidence that activation of specific body compartments by some nanoparticles can initiate both local and systemic reactivity. All these findings may have serious implications for human health. What is not known is which engineered particle(s) induce cellular reactivity, how and where this might occur.
NanoReTox intends to examine the molecular and cellular reactivity of well characterised nanoparticles on a panel of primary human/mammalian cells and human cell lines originating from different target organs and exposure routes as an indicator of in vivo toxicity. The aim is to discover which features of nanoparticles confer reactivity with which cell types/target organs.
The rapid expansion of nanotechnology means there is a vast array of nanomaterials, many of which are already in industrial production. Because of the wide variety in physicochemical properties amongst different nanomaterials it is not possible at present to predict which elicit environmental harm. However, until the mechanistic associations between nanomaterial characteristics and putative toxicity are understood,determination of nanorisks will not move forward. Many recent toxicological studies have fallen short of this; furthermore many studies have led to contrasting results and interpretations about risks, possibly reflecting the diverse sources and nature of the test materials. This illustrates the importance of studying commercial and designer particles that have been fully characterised before, during and after toxicity studies. Of the many different types of engineered nanoparticles currently produced, industrially or in the laboratory, environmental risks from non-carbon-based nanoparticles are the least studied. This is despite the rapidly growing use of particles such as TiO2, ZnO, SiO2, Ag, CuO, and CdS. The chemical composition of metal nanoparticles may contribute to their having significant additional toxicity, but few studies address this.
