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Parallel Three-Dimensional Tracking of Quantum Rods Using Polarization-Sensitive Spectroscopic Photon Localization Microscopy
journal contribution
posted on 2017-06-28, 00:00 authored by Biqin Dong, Brian T. Soetikno, Xiangfan Chen, Vadim Backman, Cheng Sun, Hao F. ZhangSemiconductor
nanocrystals and their variants are widely used in biological research
as fluorescent probes. Their unique characteristics, such as intense
brightness, tunable emission properties, and resistance to photobleaching,
make them ideal candidates for single-molecule imaging and tracking
with localization precision far beyond the diffraction limit. Their
fluorescence polarization states and emission spectra can be further
utilized to probe changes in their mechanical properties and residing
nanoenvironments. We developed a three-dimensional (3D), polarization-sensitive,
spectroscopic photon localization microscopy (3D-Polar-SPLM) that
enables parallel 3D tracking of individual quantum rods (QRs) while
simultaneously capturing their fluorescence spectra and polarization
states. Using 3D-Polar-SPLM, we spatially localized individual QRs
with a lateral localization precision of 8 nm and an axial localization
precision of 35 nm. In addition, we achieved a spectral resolution
of 2 nm and a polarization angle measuring precision of 8 degrees.
The spectral profile of the fluorescence emission provided a particle-specific
signature for identifying individual QRs among the heterogeneous population,
which significantly improved the fidelity in parallel 3D tracking
of multiple QRs. We envision that this technology will provide new
possibilities to reveal the real-time molecular dynamics of biological
processes.