Stabilizing gold nanoparticles for use in X-ray computed tomography imaging of soil systems
Stabilizing gold nanoparticles for use in X-ray computed tomography imaging of soil systems
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DOI：
10.1098/rsos.190769
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发表时间：
2019-10
影响因子：
3.5
通讯作者：
C. Scotson;María Muñoz-Hernando;S. Duncan;S. Ruiz;S. Keyes;A. van Veelen;I. Dunlop;T. Roose
中科院分区：
文献类型：
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作者：
C. Scotson;María Muñoz-Hernando;S. Duncan;S. Ruiz;S. Keyes;A. van Veelen;I. Dunlop;T. Roose
本研究建立了一种金纳米颗粒体系，该体系在土壤条件下作为x射线计算机断层扫描（XCT）造影剂表现出良好的胶体稳定性。金纳米颗粒为生物学实验提供了许多有益的特性，包括：相对最小的植物毒性，材料的x射线衰减和功能化能力。然而，土壤盐度、酸度和表面电荷会诱导金纳米粒子聚集并使其不稳定，因此在生物医学应用中，聚合物涂层通常应用于金纳米粒子以增强其在体内环境中的稳定性。在这里，我们首先证明了非涂层纳米颗粒在土壤-水溶液中聚集。然后，我们展示了用聚乙二醇（PEG）层涂层防止这种聚集。为了证明这一点，聚乙二醇包覆的纳米颗粒通过含有土壤的流动柱，并被证明是稳定的；这与使用二氧化硅和氧化铝填充柱的对照实验形成对比。我们进一步确定，完全饱和土壤的包覆金纳米颗粒悬浮液至少在5天内保持稳定。最后，我们使用时间分辨XCT成像和基于图像的模型来近似纳米颗粒在水中的扩散，类似于其他典型植物营养物质在水中的扩散。总之，这些结果确定了聚乙二醇化金纳米颗粒作为土壤中XCT成像的潜在造影剂。
This investigation establishes a system of gold nanoparticles that show good colloidal stability as an X-ray computed tomography (XCT) contrast agent under soil conditions. Gold nanoparticles offer numerous beneficial traits for experiments in biology including: comparatively minimal phytotoxicity, X-ray attenuation of the material and the capacity for functionalization. However, soil salinity, acidity and surface charges can induce aggregation and destabilize gold nanoparticles, hence in biomedical applications polymer coatings are commonly applied to gold nanoparticles to enhance stability in the in vivo environment. Here we first demonstrate non-coated nanoparticles aggregate in soil-water solutions. We then show coating with a polyethylene glycol (PEG) layer prevents this aggregation. To demonstrate this, PEG-coated nanoparticles were drawn through flow columns containing soil and were shown to be stable; this is in contrast with control experiments using silica and alumina-packed columns. We further determined that a suspension of coated gold nanoparticles which fully saturated soil maintained stability over at least 5 days. Finally, we used time resolved XCT imaging and image based models to approximate nanoparticle diffusion as similar to that of other typical plant nutrients diffusing in water. Together, these results establish the PEGylated gold nanoparticles as potential contrast agents for XCT imaging in soil.