Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305-4034, USA.
Microsc Microanal. 2013 Oct;19(5):1290-7. doi: 10.1017/S143192761300192X. Epub 2013 Jun 27.
The use of nanoparticles for the diagnosis and treatment of cancer requires the complete characterization of their toxicity, including accurately locating them within biological tissues. Owing to their size, traditional light microscopy techniques are unable to resolve them. Transmission electron microscopy provides the necessary spatial resolution to image individual nanoparticles in tissue, but is severely limited by the very small analysis volume, usually on the order of tens of cubic microns. In this work, we developed a scanning transmission electron microscopy (STEM) approach to analyze large volumes of tissue for the presence of polyethylene glycol-coated Raman-active-silica-gold-nanoparticles (PEG-R-Si-Au-NPs). This approach utilizes the simultaneous bright and dark field imaging capabilities of STEM along with careful control of the image contrast settings to readily identify PEG-R-Si-Au-NPs in mouse liver tissue without the need for additional time-consuming analytical characterization. We utilized this technique to analyze 243,000 mm³ of mouse liver tissue for the presence of PEG-R-Si-Au-NPs. Nanoparticles injected into the mice intravenously via the tail vein accumulated in the liver, whereas those injected intrarectally did not, indicating that they remain in the colon and do not pass through the colon wall into the systemic circulation.
使用纳米粒子进行癌症的诊断和治疗需要对其毒性进行全面的特征描述，包括在生物组织中准确地定位它们。由于其尺寸较小，传统的光学显微镜技术无法对其进行解析。透射电子显微镜提供了在组织中对单个纳米粒子成像所需的空间分辨率，但由于分析体积非常小，通常只有几十立方微米，因此受到严重限制。在这项工作中，我们开发了一种扫描透射电子显微镜（STEM）方法，用于分析大量组织中是否存在聚乙二醇包覆的拉曼活性硅金纳米粒子（PEG-R-Si-Au-NPs）。该方法利用 STEM 的明场和暗场成像功能，以及仔细控制图像对比度设置，能够轻松识别小鼠肝组织中的 PEG-R-Si-Au-NPs，而无需进行额外的耗时分析表征。我们利用该技术分析了 243,000mm³的小鼠肝组织中是否存在 PEG-R-Si-Au-NPs。通过尾静脉静脉内注射到小鼠体内的纳米粒子在肝脏中积累，而直肠内注射的则没有，表明它们仍留在结肠中，不会穿过结肠壁进入全身循环。
