Plastic is one of the most remarkable materials ever created. It’s cheap, lightweight and endlessly versatile. It can be shaped into anything from shopping bags to lifesaving tools in hospitals, and it’s clean, safe and can be sterilised. Depending on its purpose, it can be used just once – for example, in medical settings where hygiene is critical – or kept in service for years.

Perhaps surprisingly, plastic can even have environmental benefits thanks to its light weight, which reduces fuel use in transport. But we have become so dependent on plastic that global production reached around 414 million tonnes in 2023 – a figure that continues to rise every year.

Plastic is part of countless everyday objects. Take a toothbrush: the bristles are usually nylon, while the handle is often made from lightweight polyethylene or polypropylene. A manual toothbrush might have a volume of 8.5-19 cm³. Now imagine that over time, it breaks down into microplastics – fragments smaller than five millimetres – or even nanoplastics, which are a thousand times smaller.

If microplastics can be as small as 1 micrometre (about the size of a bacterium) – or even 0.1 micrometres (roughly the size of the SARS-CoV-2 virus) – a single toothbrush could theoretically break into 8.5-19 trillion microplastics. And these particles are........

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