Direct Observation of In-Focus Plasmonic Cargos via Breaking Angular Degeneracy in Differential Interference Contrast...

Area of Science:

• Biophysics
• Nanotechnology
• Microscopy

Background:

• Plasmonic anisotropic nanoprobes are crucial for biological studies.
• Breaking angular degeneracy in their optical symmetry is a key challenge.

Purpose of the Study:

• To develop a method for breaking angular degeneracy in single gold nanorods (AuNRs).
• To visualize and track the 3D rotational behavior of AuNRs in live biological systems.

Main Methods:

• Differential Interference Contrast (DIC) microscopy-based focused orientation and position imaging (dFOPI).
• Characterization of single AuNRs within mesoporous silica shells.
• Real-time tracking of transferrin-modified AuNRs during clathrin-mediated endocytosis.

Main Results:

• Distinct doughnut-shaped DIC image patterns were observed for single AuNRs.
• Rotation-dependent patterns allowed visualization of counterclockwise/clockwise rotations without angular degeneracy.
• Three-dimensional rotational behavior of AuNRs during endocytosis was tracked in real time.
• Right-handed twisting action along the dynamin helix during cell membrane fission was visualized.

Conclusions:

• The dFOPI method effectively breaks angular degeneracy for single AuNRs.
• dFOPI enables real-time, high-resolution 3D tracking of nanoprobes in live cells.
• This technique provides new insights into cellular processes involving nanoparticle dynamics.