The Phenomics Laboratory, School of Science, RMIT University, Melbourne, VIC, 3083, Australia.
Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, 3800, Australia.
Aquat Toxicol. 2019 Aug;213:105227. doi: 10.1016/j.aquatox.2019.105227. Epub 2019 Jun 13.
The environmental impact of exposure to 3D-printed plastics as well as potential migration of toxic chemicals from 3D-printed plastics remains largely unexplored. In this work we applied leachates from plastics fabricated using a stereolithography (SLA) process to early developmental stages of zebrafish (Danio rerio) to investigate developmental toxicity and neurotoxicity. Migration of unpolymerized photoinitiator, 1-hydroxycyclohexyl phenyl ketone (1-HCHPK) from a plastic solid phase to aqueous media at up to 200 mg/L in the first 24 h was detected using gas chromatography-mass spectrometry. Both plastic extracts (LC 22.25% v/v) and 1-HCHPK (LC 60 mg/L) induced mortality and teratogenicity within 48 h of exposure. Developmental toxicity correlated with in situ generation of reactive oxygen species (ROS), an increase in lipid peroxidation and protein carbonylation markers and enhanced activity of superoxide dismutase (SOD) and glutathione-S-transferase (GST) in embryos exposed to concentrations as low as 20% v/v for plastic extracts and 16 mg/L for 1-HCHPK. ROS-induced cellular damage led to induction of caspase-dependent apoptosis which could be pharmacologically inhibited with both antioxidant ascorbic acid and a pan-caspase inhibitor. Neuro-behavioral analysis showed that exposure to plastic leachates reduced spontaneous embryonic movement in 24-36 hpf embryos. Plastic extracts in concentrations above 20% v/v induced rapid retardation of locomotion, changes in photomotor response and habituation to photic stimuli with progressive paralysis in 120 hpf larvae. Significantly decreased acetylcholinesterase (AChE) activity with lack of any CNS-specific apoptotic phenotypes as well as lack of changes in motor neuron density, axonal growth, muscle segment integrity or presence of myoseptal defects were detected upon exposure to plastic extracts during embryogenesis. Considering implications of the results for environmental risk assessment and the growing usage of 3D-printing technologies, we speculate that some 3D-printed plastic waste may represent a significant and yet very poorly uncharacterized environmental hazard that merits further investigation on a range of aquatic and terrestrial species.
暴露于 3D 打印塑料以及 3D 打印塑料中有毒化学物质潜在迁移对环境的影响在很大程度上仍未得到探索。在这项工作中，我们将立体光固化（SLA）工艺制造的塑料浸出液应用于斑马鱼（Danio rerio）的早期发育阶段，以研究发育毒性和神经毒性。使用气相色谱-质谱法检测到在最初的 24 小时内，高达 200mg/L 的未聚合光引发剂 1-羟基环己基苯基酮（1-HCHPK）从塑料固相迁移到水介质中。暴露于塑料提取物（LC 22.25%v/v）和 1-HCHPK（LC 60mg/L）48 小时内均会引起死亡和致畸性。发育毒性与原位生成的活性氧（ROS）、脂质过氧化和蛋白质羰基化标志物的增加以及超氧化物歧化酶（SOD）和谷胱甘肽-S-转移酶（GST）活性的增强相关，在暴露于低浓度（低至 20%v/v 的塑料提取物和 16mg/L 的 1-HCHPK）时即可观察到。ROS 诱导的细胞损伤导致细胞凋亡的诱导，这可以用抗氧化剂抗坏血酸和泛半胱天冬酶抑制剂进行药理学抑制。神经行为分析表明，暴露于塑料浸出液会降低 24-36 hpf 胚胎的自发胚胎运动。在浓度高于 20%v/v 的塑料提取物会引起运动迅速减慢，对光刺激的光动力反应和习惯变化，并且在 120 hpf 幼虫中会出现进行性麻痹。在胚胎发生期间暴露于塑料提取物会导致乙酰胆碱酯酶（AChE）活性显著降低，并且没有中枢神经系统特异性凋亡表型以及运动神经元密度、轴突生长、肌肉节段完整性或肌间缺陷的变化。考虑到这些结果对环境风险评估的影响以及 3D 打印技术的日益普及，我们推测一些 3D 打印塑料废物可能代表着重大且尚未得到充分描述的环境危害，值得进一步研究一系列水生和陆地物种。
