Liv Nalan, Lazić Ivan, Kruit Pieter, Hoogenboom Jacob P
Department of Imaging Science & Technology, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.
Department of Imaging Science & Technology, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.
Ultramicroscopy. 2014 Aug;143:93-9. doi: 10.1016/j.ultramic.2013.09.002. Epub 2013 Sep 20.
We investigated SEM imaging of nanoparticle biomarkers suspended below a thin membrane, with the ultimate goal of integrating functional fluorescence and structural SEM measurements of samples kept at ambient or hydrated conditions. In particular, we investigated how resolving power in liquid SEM is affected by the interaction of the electron beam with the membrane. Simulations with the Geant4-based Monte Carlo scheme developed by Kieft and Bosch (2008) [1] are compared to experimental results with suspended nanoparticles. For 20 nm and 50 nm thin membranes, we found a beam broadening of 1.5 nm and 3 nm, respectively, with an excellent agreement between simulations and experiments. 15 nm Au nanoparticles and bio-functionalized core-shell quantum dots can be individually resolved in denser clusters. We demonstrated the imaging of single EGF-conjugated quantum dots docked at filopodia during cellular uptake with both fluorescence microscopy and SEM simultaneously. These results open novel opportunities for correlating live fluorescence microscopy with structural electron microscopy.
我们研究了悬浮在薄膜下方的纳米颗粒生物标志物的扫描电子显微镜（SEM）成像，最终目标是整合在环境或水合条件下保存的样品的功能荧光和结构SEM测量。特别是，我们研究了液体SEM中的分辨能力如何受到电子束与膜相互作用的影响。将基于Geant4的蒙特卡罗方案（由Kieft和Bosch于2008年开发[1]）的模拟结果与悬浮纳米颗粒的实验结果进行了比较。对于20纳米和50纳米的薄膜，我们分别发现电子束展宽为1.5纳米和3纳米，模拟结果与实验结果高度吻合。在密度更高的簇中，可以单独分辨出15纳米的金纳米颗粒和生物功能化的核壳量子点。我们展示了在细胞摄取过程中，通过荧光显微镜和SEM同时成像丝状伪足上对接的单个表皮生长因子（EGF）共轭量子点。这些结果为将实时荧光显微镜与结构电子显微镜相关联开辟了新的机会。
