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3D Orbital Tracking in a Modified Two-photon Microscope: An Application to the Tracking of Intracellular Vesicles
Published on: October 1, 2014
Organelle tracking in a living cell with microsecond time resolution and nanometer spatial precision
Xiaolin Nan1, Peter A Sims, X Sunney Xie
1Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA.
Summary
Researchers developed a new method for tracking gold nanoparticles (GNPs) in cells with high precision. This technique reveals the step-by-step movement of molecular motors like kinesin and dynein within living cells.
Area of Science:
- Cell Biology
- Biophysics
- Nanotechnology
Background:
- Cellular organelle transport is crucial but challenging to track with high spatiotemporal resolution.
- Existing methods struggle to meet the demands of microsecond time-resolution and nanometer spatial precision.
Purpose of the Study:
- To develop a novel strategy for precise two-dimensional tracking of gold nanoparticles (GNPs) in living cells.
- To investigate the stepping behavior of molecular motors kinesin and dynein.
Main Methods:
- Utilized a quadrant photodiode in an objective-type dark-field microscope for GNP position detection.
- Implemented a feedback loop for recording long, high time-resolution trajectories.
- Achieved 25 µs time resolution and ~1.5 nm spatial precision.
Main Results:
- Successfully tracked endocytosed GNPs transported by kinesin and dynein in living cells.
- Resolved individual 8 nm steps for kinesin-driven cargo.
- Identified distinct step sizes (8, 12, 16, 20, 24 nm) for dynein-driven cargo.
Conclusions:
- The developed technique offers unprecedented precision for studying intracellular transport.
- Provides new insights into the stepping mechanisms of molecular motors in vivo.
- Enables detailed analysis of organelle movement dynamics at the nanoscale.
