Food matrix effects impact the bioavailability and toxicity of pharmaceuticals, nutraceuticals, pesticides, and engineered nanomaterials (ENMs). However, there are currently no standardized food models to test the impact of food matrix effects using in vitro gastrointestinal models. The purpose of this study was to establish a standardized food model (SFM) for evaluating the toxicity and fate of ingested ENMs and then to assess its efficacy by examining the impact of food matrix effects on the toxicity of TiO2 nanoparticles. The formulation of the SFM was based on the average composition of the US diet: 3.4% protein (sodium caseinate); 4.6% sugar (sucrose); 5.2% digestible carbohydrates (modified corn starch); 0.7% dietary fiber (pectin); 3.4% fat (corn oil); and, 0.5% minerals (sodium chloride). The SFM consisted of an oil-in-water emulsion suitable for use in both wet and dried forms. The dried form was produced by spray drying the emulsion to improve its handling and extend its shelf-life. The particle size (D32 = 135 nm), surface charge (-37.8 mV), viscosity, color (L*, a,* b* = 82.1, -2.5, 1.3), and microstructure of the wet SFM were characterized. The hydration properties, flowability (repose angle ≈ 27.9°; slide angle ≈ 28.2°), and moisture sorption isotherms of the dry SFM were comparable to commercial food powders. The potential gastrointestinal fate of the SFM was determined using a simulated gastrointestinal tract, including mouth, stomach, and small intestine steps. Conversion of the SFM into a powdered form did not impact its gastrointestinal fate. A nanotoxicology case study with TiO2 nanoparticles exposed to a tri-culture epithelial cell model showed that food matrix effects reduced ENM cytotoxicity more than 5-fold. The SFM developed in the current study could facilitate studies of the impact of food matrix effects on the gastrointestinal fate and toxicity of various types of food NPs.

中文翻译：

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开发标准化食物模型，用于研究食物基质效应对胃肠道命运和摄入纳米材料毒性的影响

食品基质效应影响药物、营养品、农药和工程纳米材料 (ENM) 的生物利用度和毒性。然而，目前还没有标准化的食物模型来使用体外胃肠道模型来测试食物基质效应的影响。本研究的目的是建立一个标准化食物模型（SFM），用于评估摄入 ENM 的毒性和归宿，然后通过检查食物基质效应对 TiO2 纳米颗粒毒性的影响来评估其功效。SFM的配方基于美国饮食的平均成分：3.4%蛋白质（酪蛋白酸钠）；4.6%糖（蔗糖）；5.2%可消化碳水化合物（改性玉米淀粉）；0.7%膳食纤维（果胶）；3.4%脂肪（玉米油​​）；以及，0.5% 矿物质（氯化钠）。SFM 由适合湿式和干式形式使用的水包油乳液组成。通过喷雾干燥乳液来生产干燥形式，以改善其操作性并延长其保质期。对湿 SFM 的粒径 (D32 = 135 nm)、表面电荷 (-37.8 mV)、粘度、颜色 (L*, a,* b* = 82.1, -2.5, 1.3) 和微观结构进行了表征。干燥 SFM 的水合特性、流动性（休止角 ≈ 27.9°；滑动角 ≈ 28.2°）和吸湿等温线与商业食品粉末相当。SFM 的潜在胃肠道命运是通过模拟胃肠道（包括口腔、胃和小肠步骤）来确定的。将 SFM 转化为粉末形式并不会影响其胃肠道命运。一项将 TiO2 纳米粒子暴露于三培养上皮细胞模型的纳米毒理学案例研究表明，食物基质效应使 ENM 细胞毒性降低了 5 倍以上。当前研究中开发的 SFM 可以促进研究食品基质效应对胃肠道命运的影响以及各类食品 NP 的毒性。