Phospholipid-bound molecular rotors: synthesis and characterization

Area of Science:

• Biochemistry
• Cell Biology
• Materials Science

Background:

• Molecular rotors are fluorescent probes used to measure viscosity.
• Existing rotors like DCVJ do not localize in cell membranes, leading to inaccurate viscosity measurements.
• Accurate measurement of cell membrane viscosity is crucial for understanding cellular functions.

Purpose of the Study:

• To develop novel molecular rotors that specifically localize to cell membranes for reliable viscosity measurements.
• To investigate the impact of phospholipid attachment on rotor performance and viscosity sensitivity.
• To explore the potential of these new probes for monitoring membrane properties like phospholipid transition temperature.

Main Methods:

• Synthesis of molecular rotors covalently attached to a phospholipid scaffold (phosphatidylcholine).
• Evaluation of rotor viscosity sensitivity and localization in artificial bilayers and live endothelial cells.
• Comparison of rotors with hydrophobic vs. hydrophilic attachment to the phospholipid.

Main Results:

• Phospholipid-bound molecular rotors exhibited viscosity sensitivity comparable to free rotors.
• Rotors attached to the hydrophobic end of phosphatidylcholine showed complete localization in the plasma membrane.
• These novel rotors enabled monitoring of phospholipid transition temperature.
• Attachment to the hydrophilic head resulted in partial loss of viscosity sensitivity.

Conclusions:

• Covalently attaching molecular rotors to the hydrophobic end of phospholipids creates effective probes for cell membrane microviscosity.
• These phospholipid-bound rotors offer improved localization and sensitivity compared to conventional rotors.
• The developed probes are suitable for studying membrane dynamics and phospholipid phase transitions in live cells.