The occurrence of nanoplastic particles (NPs) in the environment has raised concerns about the ecotoxicological risk to aquatic ecosystems. The purpose of this study was to examine the bioavailability and toxicity of 50- and 100-nm transparent polystyrene NPs to the cnidarian Hydra attenuata. The hydras were exposed to increasing concentrations of 50- and 100-nm NPs (1.25, 2.5, 5, 10, 20, 40, and 80 mg/L) for 96 h at 20 °C followed by a 24-h depuration step. Hydras were analyzed for morphological changes, bioaccumulation of NPs using a novel assay for polystyrene NPs, oxidative stress (lipid peroxidation), polar lipids, lipid-like liquid crystals (LCs), and viscosity changes in the post-mitochondrial fraction. The results revealed that the organisms accumulated detectable amounts of NP in a concentration-dependent manner for both the 50- and 100-nm NP that persisted after 24 h in clean media. Changes in morphology were observed with a 50% effect concentration of 3.6 and 18 mg/L for the 50- and 100-nm-diameter NPs respectively. However, based on the particle concentration, the 100 nm proved to be 1.7 times more toxic than the 50-nm NPs. Exposure to NPs led to decreased biomass, lipid peroxidation (LPO), increased polar lipid levels, viscosity, and formation of LCs at the intracellular level. In the more toxic NP (100 nm), NPs in tissues were correlated with LCs, polar lipids, and LPO levels. It appears that the formation of organized LCs and polar lipids of NPs in cells was involved with NP toxicity and could represent a yet unidentified, detoxifying/bioactivation mechanism against colloidal plastics in cells. In conclusion, NPs are bioavailable to hydra and lead to LPO and lipid mobilization in hydra. The capacity of increasing lipid mobilization and LCs could determine the size-dependence toxicity of NPs.

中文翻译：

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聚苯乙烯纳米粒子对刺胞蛇头蛇的检测，生物物理效应和毒性。

环境中纳米塑料颗粒（NPs）的出现引起了人们对水生生态系统的生态毒理风险的关注。这项研究的目的是检查50纳米和100纳米透明聚苯乙烯NPs对虫刺Hy的生物利用度和毒性。在20°C下，将九头蛇暴露于浓度递增的50和100 nm NPs（1.25、2.5、5、10、20、40和80 mg / L）中96小时，然后进行24 h净化步骤。使用新颖的聚苯乙烯NPs分析，氧化应激（脂质过氧化），极性脂质，类脂质液晶（LCs）和线粒体后级分粘度变化，分析了九头蛇的形态学变化，NPs的生物积累。结果表明，对于在清洁培养基中24小时后仍存在的50和100 nm NP，生物体以浓度依赖的方式积累了可检测量的NP。观察到形态变化，直径为50和100 nm的NP的50％效应浓度分别为3.6和18 mg / L。但是，基于粒子浓度，事实证明100 nm的毒性是50 nm NP的1.7倍。暴露于NP会导致生物量减少，脂质过氧化（LPO），极性脂质水平增加，粘度增加以及在细胞内水平形成LC。在毒性更大的NP（100 nm）中，组织中的NP与LC，极性脂质和LPO水平相关。看来细胞中有组织的LC和NP极性脂质的形成与NP毒性有关，可能代表了一个尚未确定的，针对细胞胶体塑料的解毒/生物激活机制。总而言之，NP对水具有生物利用度，并导致水PO中的LPO和脂质动员。增加脂质动员和LC的能力可以确定NP的大小依赖性毒性。