Iron nanoparticles (NPs) have been proposed as a tool in very different fields such as environmental remediation and biomedical applications, including food fortification against iron deficiency, even if there is still concern about their safety. Here, we propose Xenopus laevis embryos as a suitable model to investigate the toxicity and the bio-interactions at the intestinal barrier of Fe3O4 and zerovalent iron (ZVI) NPs compared to Fe(II) and (III) salts in the 5 to 100 mg Fe/L concentration range using the Frog Embryo Teratogenesis Assay in Xenopus (FETAX). Our results demonstrated that, at concentrations at which iron salts induce adverse effects, both iron NPs do not cause acute toxicity or teratogenicity even if they accumulate massively in the embryo gut. Prussian blue staining, confocal and electron microscopy allowed mapping of iron NPs in enterocytes, along the paracellular spaces and at the level of the basement membrane of a well-preserved intestinal epithelium. Furthermore, the high bioaccumulation factor and the increase in embryo length after exposure to iron NPs suggest greater iron intake, an essential element for organisms. Together, these results improve the knowledge on the safety of orally ingested iron NPs and their interaction with the intestinal barrier, useful for defining the potential risks associated with their use in food/feed fortification.

中文翻译：

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在非洲爪蟾胚胎中评估铁纳米颗粒的生物相互作用，这是一种研究摄入纳米颗粒安全性的模型。

铁纳米颗粒（NPs）已被提议作为非常不同领域的工具，例如环境修复和生物医学应用，包括针对铁缺乏症的食品强化，即使仍然担心它们的安全性。在这里，我们提出非洲爪蟾胚胎作为合适的模型，以研究Fe3O4和零价铁（ZVI）NPs与5至100 mg Fe（II）和（III）盐相比在肠道屏障上的毒性和生物相互作用。使用非洲爪蟾中的青蛙胚胎致畸试验（FETAX）测定Fe / L的浓度范围。我们的研究结果表明，在铁盐引起不良影响的浓度下，即使铁NP大量积聚在胚胎肠道中，这两种铁NP也不会引起急性毒性或致畸性。普鲁士蓝染色，共聚焦和电子显微镜可以绘制出肠细胞中，沿细胞旁空间以及保存完好的肠上皮基底膜水平的铁NP的图谱。此外，高的生物蓄积因子和暴露于铁纳米颗粒后的胚胎长度增加表明铁摄入量增加，这是生物体必不可少的元素。这些结果共同提高了对口服铁纳米粒安全性及其与肠屏障相互作用的认识，有助于确定与其在食品/饲料强化中使用相关的潜在风险。有机体必不可少的元素。这些结果共同提高了对口服铁纳米粒安全性及其与肠屏障相互作用的认识，有助于确定与其在食品/饲料强化中使用相关的潜在风险。有机体必不可少的元素。这些结果共同提高了对口服铁纳米粒安全性及其与肠屏障相互作用的认识，有助于确定与其在食品/饲料强化中使用相关的潜在风险。