Insights from a nanoparticle minuet: two-dimensional membrane profiling through silver plasmon ruler tracking

Area of Science:

• Nanotechnology and Biophysics
• Cell Biology and Membrane Dynamics

Background:

• Polymer-tethered silver nanoparticles (silver plasmon rulers) are nanoscale probes.
• They provide information on orientation and interparticle separation via optical properties.

Purpose of the Study:

• To analyze the translational and rotational motions and extension of silver plasmon rulers on cell membranes.
• To characterize the structural details of membrane compartments using optical responses of plasmon rulers.

Main Methods:

• Utilized silver plasmon rulers as probes for optical tracking of diffusion on lysed HeLa cell plasma membranes.
• Employed polarization-resolved plasmon coupling microscopy to analyze orientation and interparticle separation.
• Quantified lateral diffusion, immobilization, and confined motion of individual plasmon rulers.

Main Results:

• Observed confined lateral diffusion and immobilization of plasmon rulers, indicating cell surface compartmentalization.
• Demonstrated that plasmon ruler optical response reveals structural details of confinement regions.
• Provided quantitative metrics for the lateral heterogeneity of cell membranes on submicrometer scales.

Conclusions:

• Polarization-resolved plasmon coupling microscopy offers detailed structural characterization of membrane compartments.
• This method provides insights into underlying membrane morphology by analyzing nanoparticle dimer dynamics.
• Silver plasmon rulers are effective tools for studying nanoscale cell surface structures and dynamics.