Using radioactivity in colloid biology

Author: Stefan Schymura, from Helmholtz-Zentrum Dresden Rossendorf (HZDR)

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Radioactivity is the decay of instable atoms. This produces ionizing radiation that, at high doses, can be dangerous to our health and those of organisms. So why using it in colloid biology research? The use of radioactivity in controlled laboratory experiments comes with several outstanding benefits. Radioactive atoms can be used to label small particles. Binding a so-called radiotracer to a nanoparticle makes them findable in complex biological systems. The radiation can be detected at very low level from the outside of the sample. This allows a very sensitive detection of radiolabeled compounds at very low concentrations without complicated sample preparation.

Within the SurfBio project, radioactive material can be produced at the cyclotron particle accelerator at the HZDR Research Site Leipzig or the JSI Research Nuclear Reactor. The radioactive tracers can be safely handled in the controlled laboratory facilities at HZDR or JSI. Through the use of these capabilities it was possible to measure and visualize the fate of nanoparticles in such complex biological systems as plants and water organisms.

The risk for the environment and society that is connected to the increasing use of nanotechnology depends greatly on the dose of the nanoparticles and their fate and transformation in the environment. For example, whether or not and under what conditions a particle will dissolve has great influence on the environmental impact of these particles. Using radioactive tracers we were able to show that CeO₂ nanoparticles can partially dissolve in the digestive tract of freshwater shrimp and that it is these dissolved parts that will be transferred into the internal organs of the organisms, causing potential harm. Radioactive tracers have great potential when it comes to the investigation of nanoparticle fate in the environment. Their use enables accurate measurements at low, environmentally relevant concentrations with unprecedented experimental ease.

References:

S.Schymura et al. (2017): “Elucidating the Role of Dissolution in CeO2 Nanoparticle Plant Uptake by Smart Radiolabeling”, Angew. Chem. Int. Ed. 56(26) 7411-7414.

https://onlinelibrary.wiley.com/doi/10.1002/anie.201702421

S.Schymura et al. (2021): “Dissolution-based uptake of CeO2 nanoparticles by freshwater shrimp – a dual-radiolabelling study of the fate of anthropogenic cerium in water organisms”, Environ. Sci. Nano 8, 1934-1944.

https://pubs.rsc.org/en/content/articlelanding/2021/en/d1en00264c