Plastic pollution in marine ecosystems constitutes an important threat to marine life. For vertebrates, macro/microplastics can obstruct and/or transit into the airways and digestive tract whereas nanoplastics (NPs; < 1000 nm) have been observed in non-digestive tissues such as the liver and brain. Whether NPs cross the intestinal epithelium to gain access to the blood and internal organs remains controversial, however. Here, we show directly NP translocation across the intestinal barrier of a fish, the European seabass, Dicentrarchus labrax, ex vivo. The luminal side of median and distal segments of intestine were exposed to fluorescent polystyrene NPs (PS-NPs) of 50 nm diameter. PS-NPs that translocated to the serosal side were then detected quantitatively by fluorimetry, and qualitatively by scanning electron microscopy (SEM) and pyrolysis coupled to gas chromatography and high-resolution mass spectrometry (Py-GC-HRMS). Fluorescence intensity on the serosal side increased 15–90 min after PS-NP addition into the luminal side, suggesting that PS-NPs crossed the intestinal barrier; this was confirmed by both SEM and Py-GC-HRMS. This study thus evidenced conclusively that NPs beads translocate across the intestinal epithelium in this marine vertebrate.

海洋生态系统中的塑料污染对海洋生物构成重要威胁。对于脊椎动物，大/微塑料会阻塞和/或进入气道和消化道，而纳米塑料（NP；< 1000 nm）已在非消化组织（如肝脏和大脑）中观察到。然而，纳米粒子是否能穿过肠上皮进入血液和内脏器官仍然存在争议。在这里，我们直接展示了 NP 易位穿过鱼类（欧洲鲈鱼、 Dicentrarchus labrax）的肠道屏障，离体。将肠中段和远端段的管腔侧暴露于直径 50 nm 的荧光聚苯乙烯纳米颗粒 (PS-NP)。然后通过荧光测定法定量检测转位到浆膜侧的 PS-NP，并通过扫描电子显微镜 (SEM) 和热解结合气相色谱和高分辨率质谱 (Py-GC-HRMS) 定性检测。PS-NP 添加到管腔侧后 15-90 分钟，浆膜侧的荧光强度增加，表明 PS-NP 穿过了肠道屏障；SEM 和 Py-GC-HRMS 均证实了这一点。因此，这项研究最终证明，纳米粒子珠在这种海洋脊椎动物的肠上皮细胞中易位。