There is concern about the threat that nanoplastics (NPs) may pose to both wildlife and humans. This thesis explores the mechanisms of toxicity of polystyrene nanoparticles (PS-NPs) in chicken... Show moreThere is concern about the threat that nanoplastics (NPs) may pose to both wildlife and humans. This thesis explores the mechanisms of toxicity of polystyrene nanoparticles (PS-NPs) in chicken embryo. In Chapter 1, I review the literature on MPs and NPs, and their potential risks to humans and animals. In Chapter 2, I show that the exposure of chicken embryos to PS-NPs produces malformations in the neural tube, eyes, and tail. Chapter 3 details the heart malformations caused by PS-NPs. I propose that the mechanisms of PS-NP toxicity include the selective binding of PS-NPs to neural crest cells, leading to the death and impaired migration of those cells (Chapter 4). My data support this model, indicating that most of the malformations I observe are in organs that depend for their normal development on neural crest cells. My findings are a matter of concern given the large and growing burden of nanoplastics in the environment, and the fact that they are being considered as drug-delivery agents in nanomedicine. They also suggest that NPs may pose a potential health risk to the developing embryo. Further work is needed to determine how PS-NPs become distributed in the body. Show less
Wang, M.R.; Rücklin, M.; Poelmann, R.E.; Mooij, C.L. de; Fokkema, M.; Lamers, G.E.M.; ... ; Richardson, M.K. 2023
Nanomaterials are widespread in the human environment as pollutants, and are being actively developed for use in human medicine. We have investigated how the size and dose of polystyrene... Show moreNanomaterials are widespread in the human environment as pollutants, and are being actively developed for use in human medicine. We have investigated how the size and dose of polystyrene nanoparticles affects malformations in chicken embryos, and have characterized the mechanisms by which they interfere with normal development. We find that nanoplastics can cross the embryonic gut wall. When injected into the vitelline vein, nanoplastics become distributed in the circulation to multiple organs. We find that the exposure of embryos to polystyrene nanoparticles produces malformations that are far more serious and extensive than has been previously reported. These malformations include major congenital heart defects that impair cardiac function. We show that the mechanism of toxicity is the selective binding of polystyrene nanoplastics nanoparticles to neural crest cells, leading to the death and impaired migration of those cells. Consistent with our new model, most of the malformations seen in this study are in organs that depend for their normal development on neural crest cells. These results are a matter of concern given the large and growing burden of nanoplastics in the environment. Our findings suggest that nanoplastics may pose a health risk to the developing embryo. Show less
