Radiation damage behavior of soft matter in ultrafast cryo-electron microscopy (cryo-UEM)

作者：Yimin Zhao, Qi Chen, Chunhui Zhu, Yun Zhu, Yongzhao Zhang, Tongnian Gu, Huanfang Tian, Wentao Wang, Siyuan Huang, Huaixin Yang, Jianqi Li, Fei Sun · 发表于：The Innovation Life · 年份：2025 · DOI：10.59717/j.xinn-life.2025.100145 · 被引用次数：5 · 研究领域：Advanced Electron Microscopy Techniques and Applications、Advanced X-ray Imaging Techniques、Force Microscopy Techniques and Applications

Whether time-modulated pulsed-electron imaging can mitigate sample radiation damage is still controversial. The effectiveness of such mitigation and relevant potential applications in cryo-EM remain to be explored. Herein, we built an ultrafast cryo-EM system based on an ultrafast laser. Using such system and the saturated aliphatic hydrocarbon compounds (C44H90), the diffraction-intensity fading curves and corresponding critical electron doses (Ne) of samples were carefully measured under different imaging modes, temperatures, imaging dose rates and pulsed repetition rates. Our experimental results demonstrate that the fading curves and Ne values of C44H90 crystals show no correlation with the imaging electron dose rates. As the temperature decreased, the Ne values of the sample increased, indicating a cryoprotective effect on sample radiation damage. Interestingly, at constant temperature, the fading curves and Ne values of the sample in multi-electron-packet and near-single-electron-packet pulsed modes are all approximately the same as those in conventional continuous electron-beam mode, even when obtained at different pulsed repetiti...