Institute of Atomic and Molecular Sciences, Academia Sinica, 10617 Taipei, Taiwan.
Nanoscale. 2017 May 18;9(19):6567-6574. doi: 10.1039/c7nr00604g.
The investigation of intracellular transport at the molecular scale requires measurements at high spatial and temporal resolutions. We demonstrate the label-free, direct imaging and tracking of native cell vesicles in live cells at an ultrahigh spatiotemporal resolution. Using coherent brightfield (COBRI) microscopy, we monitor individual cell vesicles traveling inside the cell with nanometer spatial precision in 3D at 30 000 frames per second. The stepwise directional motion of the vesicle on the cytoskeletal track is clearly resolved. We also observe the repeated switching of the transport direction of the vesicle in a continuous trajectory. Our high-resolution measurement unveils the transient pausing and subtle bidirectional motion of the vesicle, taking place over tens of nanometers in tens of milliseconds. By tracking multiple particles simultaneously, we found strong correlations between the motions of two neighboring vesicles. Our label-free ultrahigh-speed optical imaging provides the opportunity to visualize intracellular cargo transport at the nanoscale in the microsecond timescale with minimal perturbation.
在分子尺度上研究细胞内运输需要在高空间和时间分辨率下进行测量。我们展示了在超高速时空分辨率下对活细胞中原位细胞小泡进行无标记、直接成像和跟踪的技术。我们使用相干明场（COBRI）显微镜，以每秒 30000 帧的速度在 3D 中以纳米级空间精度监测单个细胞小泡在细胞内的运动。可以清楚地分辨出小泡在细胞骨架轨道上的逐步定向运动。我们还观察到小泡在连续轨迹中运输方向的反复切换。我们的高分辨率测量揭示了小泡在数十毫秒内发生在数十纳米范围内的短暂停顿和微妙的双向运动。通过同时跟踪多个粒子，我们发现两个相邻小泡的运动之间存在很强的相关性。我们的无标记超高速度光学成像提供了在微秒时间尺度内以最小干扰可视化纳米尺度细胞内货物运输的机会。
