Meng Xuanhui, Sonn-Segev Adar, Schumacher Anne, Cole Daniel, Young Gavin, Thorpe Stephen, Style Robert W, Dufresne Eric R, Kukura Philipp
Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3TA, U.K.
ETH Zürich, 8092 Zürich, Switzerland.
ACS Photonics. 2021 Oct 20;8(10):3111-3118. doi: 10.1021/acsphotonics.1c01268. Epub 2021 Oct 8.
Single particle tracking has found broad applications in the life and physical sciences, enabling the observation and characterization of nano- and microscopic motion. Fluorescence-based approaches are ideally suited for high-background environments, such as tracking lipids or proteins in or on cells, due to superior background rejection. Scattering-based detection is preferable when localization precision and imaging speed are paramount due to the in principle infinite photon budget. Here, we show that micromirror-based total internal reflection dark field microscopy enables background suppression previously only reported for interferometric scattering microscopy, resulting in nanometer localization precision at 6 μs exposure time for 20 nm gold nanoparticles with a 25 × 25 μm field of view. We demonstrate the capabilities of our implementation by characterizing sub-nanometer deterministic flows of 20 nm gold nanoparticles at liquid-liquid interfaces. Our results approach the optimal combination of background suppression, localization precision, and temporal resolution achievable with pure scattering-based imaging and tracking of nanoparticles at interfaces.
单粒子追踪已在生命科学和物理科学中得到广泛应用，能够对纳米级和微观运动进行观察和表征。基于荧光的方法非常适合高背景环境，例如追踪细胞内或细胞上的脂质或蛋白质，因为其具有出色的背景抑制能力。当定位精度和成像速度至关重要时，基于散射的检测更具优势，因为原则上其光子预算是无限的。在此，我们展示了基于微镜的全内反射暗场显微镜能够实现此前仅在干涉散射显微镜中报道过的背景抑制，在25×25μm视场下，对于20nm金纳米颗粒，在6μs曝光时间内可实现纳米级定位精度。我们通过表征液 - 液界面处20nm金纳米颗粒的亚纳米级确定性流动来展示我们所实现方法的能力。我们的结果接近了在界面处基于纯散射成像和追踪纳米颗粒可实现的背景抑制、定位精度和时间分辨率的最佳组合。
