Nanomaterials are widely distributed in the human environment as pollutants and are being actively developed for use in human medicine. Microplastics and nanoplastics (MPs and NPs) are small plastic particles relevant to human health.

The potentially harmful effects of MPs and NPs have mainly been studied in aquatic organisms, including crustaceans (eg Daphnia magna), gastropods and fish (eg zebrafish). These studies have shown that microplastics and nanoplastics can cause a range of toxic effects.

A new study at the Leiden Institute of Biology has looked at the extreme effects that nanoparticles of polystyrene can have. Scientists have studied how the size and dose of polystyrene nanoparticles affect malformations in chicken embryos. They also characterized the mechanisms by which they interfere with normal development.

Meiru Wang, a researcher at the Institute of Biology Leiden, said: “We see deformities in the nervous system, heart, eyes and other parts of the face. We used a high concentration of polystyrene particles that normally would not be present in an organism. But it shows what nanoplastics can do in extreme cases on very young embryos. And it also gives us a handle on what can happen less badly in the development phase.”

Scientists found that embryonic neural crest cells are targeted by nanoplastics. All vertebrates develop these stem cells quite early in their development. Starting in the area that will become the spinal cord, the cells of the neural crest migrate to form part of the nervous system. They are also found in the arteries, heart, and face, among other vital organs.

Michael Richardson, Wang’s supervisor, explains: “But when nanoparticles surround the cells of the neural crest, the migration of those cells is disrupted. This causes growth disorders. When you know the mechanism, everything else falls into place. We think they attach to the neural crest cells, causing the cells to die. Neural crest cells are sticky, so nanoparticles can adhere to them and thereby disrupt organs that depend on these cells for development. I like the dough making metaphor. When making bread, for example, you put flour on it to make it no longer sticky. In this case, however, it ruins the migration of the neural cells.”

Martina Vijver, is Wang’s supervisor. ‘Because nanoplastics are so small, you cannot see them with conventional microscopes. That makes it difficult to do research. We can only see them if they are fluorescently labeled,” Richardson explained. ‘Collaboration was the best choice, because you can’t do this kind of research as a one-man band.’

The researcher continues: ‘At Naturalis Biodiversity Center in Leiden, Martin Rücklin and Bertie Joan van Heuven were able to make 3D reconstructions of the embryos, so that we could see the malformations. And with the high-resolution synchrotron Switzerland, we were able to see what’s happening in the heart. Experienced researchers from the LUMC helped determine what we see.’

‘In research, everything is a question mark and you get the chance to fill in the gaps. I have many wonderful supervisors and colleagues who encourage and encourage me. This research is just one step towards seeing the ultimate effects of nanoplastics in our environment. And especially as people are now looking at its use in human medicine, we feel we need to be careful before these drastic effects are seen in humans.”

Magazine reference:

  1. Wang, M., Rücklin, M., Poelmann, RE, de Mooij, CL, Fokkema, M., Lamers, GE, … & Richardson, MK (2023). Nanoplastics cause extensive congenital malformations during embryonic development by passively targeting neural crest cells. Environment International, 107865. DOI: 10.1016/j.envint.2023.107865