The safe and effective use of nanoparticles for biological applications requires a many-pronged classification of nanoparticle properties (material, coating, size, and shape) as well as biological environments. A Langmuir-film-based synthetic membrane system containing an active transmembrane protein, glucose-6-phosphatase (G6Pase), was employed to investigate the effects nanoparticle exposure as a function of membrane surface pressure. The activity of G6Pase after exposure to 5 nm gold nanoparticles functionalized with anionic, cationic, and neutral ligand coatings was found to increase by as much as 300% for both anionic and neutral particles at surface pressures less than 30 mN/m, indicating significant nanoparticle–protein interactions. Atomic force microscopy imaging was used to track the distribution of nanoparticles and G6Pase within the membranes and correlate changes in activity to the distribution of G6Pase in the membrane. Conditions which enabled the redistribution of protein in the form of solubilization or aggregation within the membrane were identified for each class of nanoparticles. This investigation demonstrates the importance of the phospholipid environment surrounding membrane proteins during exposure to nanoparticles which can impact the nanoparticle fate in terms of uptake as well as potential effects on membrane protein activity.

中文翻译：

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带电和中性金纳米粒子与基于Langmuir膜的合成膜的相互作用不同：纳米粒子摄取和膜蛋白活性的含义。

为了将纳米颗粒安全有效地用于生物应用，需要对纳米颗粒的性质（材料，涂层，尺寸和形状）以及生物环境进行多方面的分类。基于Langmuir膜的包含活性跨膜蛋白葡萄糖6磷酸酶（G6Pase）的合成膜系统用于研究纳米颗粒暴露与膜表面压力的关系。发现在暴露于表面压力小于30 mN / m的阴离子和中性颗粒时，暴露于用阴离子，阳离子和中性配体涂层功能化的5 nm金纳米颗粒后，G6Pase的活性增加多达300％，表明存在显着的纳米颗粒–蛋白质相互作用。原子力显微镜成像用于追踪纳米颗粒和G6Pase在膜内的分布，并将活性变化与G6Pase在膜内的分布相关联。对于每一类纳米颗粒，确定了能够以增溶或聚集形式在膜内重新分布蛋白质的条件。这项研究证明了在暴露于纳米颗粒期间膜蛋白周围的磷脂环境的重要性，这在摄取以及对膜蛋白活性的潜在影响方面都可能影响纳米颗粒的命运。对于每一类纳米颗粒，确定了能够以增溶或聚集形式在膜内重新分布蛋白质的条件。这项研究证明了在暴露于纳米颗粒期间膜蛋白周围的磷脂环境的重要性，这在摄取以及对膜蛋白活性的潜在影响方面都可能影响纳米颗粒的命运。对于每一类纳米颗粒，确定了能够以增溶或聚集形式在膜内重新分布蛋白质的条件。这项研究证明了在暴露于纳米颗粒期间膜蛋白周围的磷脂环境的重要性，这在摄取以及对膜蛋白活性的潜在影响方面都可能影响纳米颗粒的命运。