Imaging plasma membrane phase behaviour in live cells using a thiophene-based molecular rotor

Area of Science:

• Biophysics
• Membrane Biology
• Fluorescence Spectroscopy

Background:

• Molecular rotors are crucial for measuring microscopic viscosity in lipid bilayers.
• Existing probes struggle to uniformly stain phase-separated lipid bilayers.
• Understanding lipid domain dynamics is vital for cell membrane function.

Purpose of the Study:

• To develop and validate a novel membrane-targeting viscosity-sensitive fluorophore.
• To assess the probe's ability to stain both ordered and disordered lipid domains equally.
• To investigate lipid ordering and viscosity in artificial and live cell membranes.

Main Methods:

• Synthesis of a thiophene-based viscosity-sensitive fluorophore.
• Application of the fluorophore to artificial lipid bilayers with varying compositions.
• Imaging and viscosity measurements in live cell plasma membranes using fluorescence microscopy.

Main Results:

• The thiophene-based fluorophore demonstrated equal affinity for both ordered and disordered lipid domains.
• The probe successfully reported on viscosity changes in artificial lipid bilayers.
• Viscosity and ordering within live cell plasma membranes were effectively probed.

Conclusions:

• A novel molecular rotor with balanced affinity for lipid domains was successfully developed.
• This fluorophore serves as a versatile tool for studying membrane microviscosity in complex lipid environments.
• The findings enable more accurate investigations of membrane dynamics in biological systems.