The use of engineered nanomaterials (ENMs) in foods and consumer products is rising, increasing the potential for unintentional ingestion. While the cytotoxicity of many ENMs has been investigated, less attention has been given to adverse impact on the intestinal barrier integrity. Chronical disruption of gastrointestinal integrity can have far reaching health implications. Using fully differentiated Caco-2 cells, the perturbation of intestinal barrier function and cytotoxicity were investigated for 20 metal, metal oxide, and metal sulfide ENMs. Caco-2 cells were exposed to 50 μg/mL ENMs for 24 hours. ENM formulations were characterized at 0 and 24 hours, and In Vitro Sedimentation, Diffusion and Dosimetry Modeling was applied to calculate the effective dose of exposure during 24 hours. The apparent permeability coefficient (Papp) was determined for fluorescent labeled dextran (3,000 Da) and tight junction integrity was evaluated by immunofluorescence microscopy. Cytotoxicity was investigated by determining lactate dehydrogenase release (LDH) and cell metabolic activity (tetrazolium based MTS) assays. Four ENMs led to significantly increased Papp, (15.8% w/w% Ag-SiO2 nanoparticle (NP), 60 nm CdS NP, 100 nm V2O5 flakes, and 50 nm ZnO NP), while one ENM (20 nm MgO NP) decreased Papp. With the exception of CdS NP, significantly increased Papp was not connected with cell cytotoxicity. The calculated effective dose concentration was not correlated with increased Papp. Our results illustrate that while many metal, metal oxide, and metal sulfide ENMs do not adversely affect monolayer integrity or induce cytotoxicity in differentiated Caco-2 cells, a subset of ENMs may compromise the intestinal integrity. This study demonstrated the use of differentiated Caco-2 monolayer and Papp as an endpoint to identify and prioritize ENMs that should be investigated further. The interaction between ENMs and the intestinal epithelium needs to be evaluated to understand potential intestinal barrier dysfunction and resulting health implications.

中文翻译：

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研究二十种金属、金属氧化物和金属硫化物纳米粒子对分化的 Caco-2 单层完整性的影响

工程纳米材料 (ENM) 在食品和消费品中的使用正在增加，增加了无意摄入的可能性。虽然已经研究了许多 ENM 的细胞毒性，但对肠道屏障完整性的不利影响却很少受到关注。胃肠道完整性的慢性破坏会对健康产生深远的影响。使用完全分化的 Caco-2 细胞，研究了 20 种金属、金属氧化物和金属硫化物 ENM 对肠道屏障功能和细胞毒性的扰动。Caco-2 细胞暴露于 50 μg/mL ENM 24 小时。ENM 制剂在 0 和 24 小时进行表征，并应用体外沉积、扩散和剂量学建模来计算 24 小时内的有效暴露剂量。对荧光标记的葡聚糖 (3,000 Da) 测定表观渗透系数 (Papp)，并通过免疫荧光显微镜评估紧密连接的完整性。通过确定乳酸脱氢酶释放 (LDH) 和细胞代谢活性（基于四唑的 MTS）测定来研究细胞毒性。四种 ENM 导致 Papp 显着增加（15.8% w/w% Ag-SiO2 纳米颗粒 (NP)、60 nm CdS NP、100 nm V2O5 薄片和 50 nm ZnO NP），而一种 ENM（20 nm MgO NP）降低帕普。除 CdS NP 外，显着增加的 Papp 与细胞毒性无关。计算出的有效剂量浓度与增加的 Papp 无关。我们的结果表明，虽然许多金属、金属氧化物、和金属硫化物 ENM 不会对分化的 Caco-2 细胞的单层完整性产生不利影响或诱导细胞毒性，一部分 ENM 可能会损害肠道完整性。这项研究证明了使用分化的 Caco-2 单层和 Papp 作为端点来识别和优先考虑应进一步研究的 ENM。需要评估 ENM 与肠上皮之间的相互作用，以了解潜在的肠道屏障功能障碍和由此产生的健康影响。