Published 2021-06-10This post is also available in Swedish
Cedervall on nanoparticles, toxicity and science theatre
Today, what started with an insight into crocodiles in South Africa has evolved into studies on fish in Sweden. Tommy Cedervall is researching nanoparticles and their toxicity in the natural environment. The risks associated with nanoplastics are among the topics under scrutiny in the Mistra Environmental Nanosafety research programme.
In 2005, Tommy Cedervall had a research fellowship at University College Dublin and in biochemistry at Lund University, studying nanosafety. During his fellowship, a laboratory employee in Lund watched a programme about crocodiles in a South African river. Despite their fatty tails, the crocodiles were dying of fat deficiency in winter. It turned out that a factory upstream was releasing nanoparticles. This example captured the research group’s interest.
‘We weren’t allowed to work on crocodiles, so we started researching plankton, algae and fish. We found that the nanoparticles were absorbed into their tissue and travelled up the food chain, affecting fat levels and behaviour in fish. The fish became more sluggish and had weaker hunting instincts. And despite suffering from hunger, they were less likely to look for food and eat than the control groups,’ Cedervall explains.
Today, Tommy Cedervall is a researcher in biochemistry and structural biology at Lund University and programme director of Mistra Environmental Nanosafety. ‘Curiosity and chance’ is how he describes what started him on a research career. He was actually studying to be a teacher, but when he realised that being credited for courses in mathematics and biology was not possible, he dropped out and started studying biology instead. At one point, when Cedervall accompanied a student friend on a visit to a professor who was working on streptococci, the two were offered doctoral positions on the spot. His curiosity made him accept, and he embarked on his career path as a protein chemist in medical chemistry.
A few years later, during his research fellowship at Lund University and University College Dublin (when crocodiles captured his attention), he studied nanoparticles and protein, and was increasingly interested in ecotoxicity. He was among those who opened up the protein corona as a field of study — one that has now grown greatly.
‘The protein corona is a surface of protein that forms on nanoparticles when they enter biofluids and affects how the body reacts to the particles and how long they stay in the body,’ Cedervall explains.
Impact of nanoplastics
Mistra Environmental Nanosafety began in 2014. In its first phase, corona formations were discussed: what they mean for nanoparticles, what happens when the particles are released into the environment and how their toxicity is affected. These discussions have formed the basis of the current second phase of the programme.
‘We want to look more at the various chemical changes the particles undergo — what happens when they get out in the natural environment, how the particles are bound in organic matter and the surroundings, what aggregations and formations of corona can result, and how this affects toxicity. Our research is about science, focusing on the aquatic environment, but we also have a big work package focusing on nanoparticle regulations.’
Regulations and controls imposed on industry require life-cycle assessments of nanoparticles to be carried out. This is a major challenge for manufacturers and importers. In Mistra Environmental Nanosafety, a regulation nanodatabase is now being established and operated. The programme also looks at how risk assessment as a method can be revised to include existing data on toxicity and ecotoxicity as well, and can thereby provide decision-makers with significant results.
Cedervall’s own research focuses on testing the toxicity of various nanoparticles, and the scientists are now conducting studies on nanoplastics. Just as a protein corona is formed in biofluid, a ‘biocorona’ or ‘ecocorona’ forms around nanoparticles in the environment. The researchers are now testing the toxicity of the particles with and without the corona.
A previous experiment tested concentrations of nanoplastics and other particles by studying their effect on Daphnia, a zooplankton genus. A specific type of polystyrene nanoparticle had little effect on the plankton in high concentrations for a brief exposure period, they found. However, it had an adverse impact on them, with fatal impact, in low concentrations when exposure was prolonged.
‘We don’t yet know how nanoplastics affect nature. When we produced the very first article that showed how fish were affected by nanoplastics, it received a lot of attention since people hadn’t realised they would end up in the environment. Now they’re feverishly looking for ways to detect the plastics we expect to be there. Personally, I’m worried about nanoplastics, while plastic is a superb material with great benefits, and I’m happy about the knowledge development now under way in this area.’
Science theatre valuable for researchers
The biggest challenge for Mistra Environmental Nanosafety is now to link the scientific side of the programme to the side about regulation and the social sciences, Cedervall thinks. Industrial firms are interested but, due to the current pandemic, the stages concerned with innovation and stakeholder dialogues have not really got off the ground. Industry also wants to know how nanomaterials are perceived in society. Cedervall refers to small-scale studies conducted at Lund University showing that although people are generally in favour of nanotechnology, they are opposed to nanoparticles.
‘If we’re honest with ourselves, it’s related to how we describe the nano-area in our communication with the public. Nanotechnology is perceived as positive because it brings to mind new solar panels and medicine, while nanoparticles are the technology’s downside.’
Alongside Mistra Environmental Nanosafety, Cedervall and the other researchers at Lund University are collaborating with the Sagohuset (‘Story House’) theatre group. In the project Den rätta vägen, plast på gott och ont (‘The Right Way: plastic for better or worse’), which comprises science theatre and workshops, the researchers tell the audience about nanoparticles and a theatre group interprets the science and the findings in performances for upper secondary schools.
‘It’s great fun! And immensely valuable for us as researchers since completely new questions come up — very different from the ones we usually get. It’s an extremely exciting process where we get to explain our research in a different, deeper way. I’ve involved my whole research group, and it’s bringing us together in a way that lots of people appreciate.’