Micromirror total internal reflection microscopy for high-performance single particle tracking at interfaces

Journal article

Single particle tracking has found broad applications in the life and physical sciences, enabling the observation and characterisation 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 localisation 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 nm localisation precision at 6 $\mu$s exposure time for 20 nm gold nanoparticles with a 25 x 25 $\mu$m$^{2}$ field of view. We demonstrate the capabilities of our implementation by characterizing sub-nm deterministic flows of 20 nm gold nanoparticles at liquid-liquid interfaces. Our results approach the optimal combination of background suppression, localisation precision and temporal resolution achievable with pure scattering-based imaging and tracking of nanoparticles at regular interfaces.

Authors: Meng, X; Sonn-Segev, A; Schumacher, A; Cole, D; Young, G

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Chemical Society
• Journal: ACS Photonics
• Volume: 8
• Issue: 10
• Pages: 3111–3118
• Publication date: 2021-10-08
• DOI: 10.1021/acsphotonics.1c01268
• EISSN: 2330-4022
• Language: English
• Keywords: FFR; physics.optics