Molecular Biophysics and Integrative Bioimaging Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
Department of Chemistry, University of Washington , Seattle, Washington 98195, United States.
ACS Nano. 2017 Oct 24;11(10):10583-10590. doi: 10.1021/acsnano.7b06081. Epub 2017 Sep 28.
In situ electron microscopy provides remarkably high spatial resolution, yet electron beam irradiation often damages soft materials and perturbs dynamic processes, requiring samples to be very robust. Here, we instead noninvasively image the dynamics of metal and polymer nanoparticles in a liquid environment with subdiffraction resolution using cathodoluminescence-activated imaging by resonant energy transfer (CLAIRE). In CLAIRE, a free-standing scintillator film serves as a nanoscale optical excitation source when excited by a low energy, focused electron beam. We capture the nanoscale dynamics of these particles translating along and desorbing from the scintillator surface and demonstrate 50 ms frame acquisition and a range of imaging of at least 20 nm from the scintillator surface. Furthermore, in contrast with in situ electron microscopy, CLAIRE provides spectral selectivity instead of relying on scattering alone. We also demonstrate through quantitative modeling that the CLAIRE signal from metal nanoparticles is impacted by multiplasmonic mode interferences. Our findings demonstrate that CLAIRE is a promising, noninvasive approach for super-resolution imaging for soft and fluid materials with high spatial and temporal resolution.
原位电子显微镜提供了极高的空间分辨率，但电子束辐照通常会损坏软材料并扰乱动态过程，这要求样品具有很强的稳定性。在这里，我们使用通过共振能量转移的受激阴极发光激活成像（CLAIRE），以亚衍射分辨率非侵入式地原位观察液体环境中金属和聚合物纳米颗粒的动力学。在 CLAIRE 中，当用低能量聚焦电子束激发时，独立的闪烁体薄膜可用作纳米级光学激发源。我们捕捉到这些粒子在闪烁体表面上的平移和脱附的纳米级动力学，并展示了 50ms 帧采集和至少 20nm 范围的从闪烁体表面的成像。此外，与原位电子显微镜不同，CLAIRE 提供了光谱选择性，而不是仅依赖于散射。我们还通过定量建模证明，金属纳米颗粒的 CLAIRE 信号受到多等离子体模干扰的影响。我们的研究结果表明，CLAIRE 是一种很有前途的、非侵入式的软质和流体材料的超高分辨率成像方法，具有高空间和时间分辨率。
