Given the global abundance and environmental persistence, exposure of humans and (aquatic) animals to micro- and nanoplastics is unavoidable. Current evidence indicates that micro- and nanoplastics can be taken up by aquatic organism as well as by mammals. Upon uptake, micro- and nanoplastics can reach the brain, although there is limited information regarding the number of particles that reaches the brain and the potential neurotoxicity of these small plastic particles. Earlier studies indicated that metal and metal-oxide nanoparticles, such as gold (Au) and titanium dioxide (TiO2) nanoparticles, can also reach the brain to exert a range of neurotoxic effects. Given the similarities between these chemically inert metal(oxide) nanoparticles and plastic particles, this review aims to provide an overview of the reported neurotoxic effects of micro- and nanoplastics in different species and in vitro. The combined data, although fragmentary, indicate that exposure to micro- and nanoplastics can induce oxidative stress, potentially resulting in cellular damage and an increased vulnerability to develop neuronal disorders. Additionally, exposure to micro- and nanoplastics can result in inhibition of acetylcholinesterase activity and altered neurotransmitter levels, which both may contribute to the reported behavioral changes. Currently, a systematic comparison of the neurotoxic effects of different particle types, shapes, sizes at different exposure concentrations and durations is lacking, but urgently needed to further elucidate the neurotoxic hazard and risk of exposure to micro- and nanoplastics.

中文翻译：

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塑料大脑：微米和纳米塑料的神经毒性。

考虑到全球的丰富性和环境持久性，不可避免的是人类和（水生）动物暴露于微米和纳米塑料中。目前的证据表明，水生生物以及哺乳动物都可以吸收微米和纳米塑料。吸收后，尽管有关到达大脑的颗粒数量以及这些小塑料颗粒的潜在神经毒性的信息有限，但微量和纳米塑料仍可以到达大脑。早期的研究表明，金属和金属氧化物纳米粒子，例如金（Au）和二氧化钛（TiO2）纳米粒子，也可以到达大脑，从而发挥一系列神经毒性作用。考虑到这些化学惰性的金属（氧化物）纳米粒子与塑料粒子之间的相似性，这篇综述旨在概述所报道的微塑料和纳米塑料在不同物种和体外的神经毒性作用。合并后的数据尽管是零散的，但表明暴露于微塑料和纳米塑料会诱导氧化应激，从而潜在地导致细胞损伤和发展为神经元疾病的脆弱性增加。此外，接触微塑料和纳米塑料可导致抑制乙酰胆碱酯酶活性和改变神经递质水平，这两者均可能导致所报道的行为改变。当前，缺乏在不同暴露浓度和持续时间下不同颗粒类型，形状，大小的神经毒性作用的系统比较，但是迫切需要进一步阐明神经毒性危害和暴露于微塑料和纳米塑料的风险。