Enhanced stability and fluidity in droplet on hydrogel bilayers for measuring membrane protein diffusion

Area of Science:

• Biophysics
• Materials Science
• Cell Biology

Background:

• Artificial lipid bilayers are crucial for studying membrane protein function.
• Existing methods for creating lipid bilayers can be challenging for microscopy and long-term stability.

Purpose of the Study:

• To develop a novel method for creating stable artificial lipid bilayers suitable for single-molecule fluorescence microscopy.
• To investigate the diffusion and insertion mechanism of membrane proteins, specifically alpha-hemolysin, within these artificial bilayers.

Main Methods:

• Formation of artificial lipid bilayers by contacting an aqueous droplet with a hydrogel support in a lipid-oil solution.
• Utilizing single-molecule fluorescence microscopy to observe lipid mobility and membrane protein diffusion.
• Comparing the lateral mobility of the heptameric alpha-hemolysin toxin with its monomeric precursor.

Main Results:

• Droplet on hydrogel bilayers (DHBs) demonstrate high lipid mobilities, comparable to unsupported lipid bilayers.
• DHBs exhibit remarkable stability, persisting for several weeks.
• A decrease in lateral mobility was observed for heptameric alpha-hemolysin compared to its monomer, suggesting binding without insertion.

Conclusions:

• Droplet on hydrogel bilayers (DHBs) provide a robust and versatile platform for biophysical studies of lipid membranes.
• The observed diffusion patterns of alpha-hemolysin support models of its membrane insertion mechanism.
• This technique facilitates advanced investigations into membrane protein dynamics and interactions.