Microplastics and nanoplastics (MNPs) are increasingly recognized as pervasive environmental exposures that can enter the human body, raising growing concern about their potential consequences for human health. However, their biodistribution, persistence and possible neurological effects remain poorly understood. Li et al. addressed this gap by applying complementary microscopy-based analyses to compare human brain tumour samples with patients with brain tumours, alongside healthy human post-mortem brain tissues to quantify MNP burden, characterize particle composition and spatial distribution.

Hypothesizing that the blood–brain barrier was compromised in the context of brain cancers enabling efficient MNP entry into the brain, the authors compared MNP distribution between pathological tissues and healthy tissues. MNPs were detected in all tissue samples regardless of disease, which suggests that MNPs may cross the blood–brain barrier irrespective of pathological changes. However, the abundance of microplastics in healthy tissue was lower than that in peri-glioma tissue, indicating that the cancerous brain is more receptive to MNP accumulation.