Dynamic force spectroscopy on supported lipid bilayers: effect of temperature and sample preparation

Area of Science:

• Biophysics
• Materials Science
• Cell Biology

Background:

• Biological membranes experience constant forces, influencing protein behavior.
• Understanding membrane mechanics is crucial for integral and membrane-associated proteins exhibiting mechanosensitivity.

Purpose of the Study:

• To investigate the mechanical properties of supported lipid bilayers (SLBs) under perpendicular forces.
• To determine how interleaflet coupling affects SLB mechanical response and punch-through events.
• To analyze the dynamic force spectroscopy (DFS) behavior of SLBs.

Main Methods:

• Utilized force spectroscopy, specifically atomic force spectroscopy (AFM), to probe SLBs.
• Measured lipid bilayer mechanical properties and punch-through forces.
• Conducted dynamic force spectroscopy (DFS) experiments varying temperature and cantilever spring constant.

Main Results:

• Uncoupled bilayers showed sequential tip penetration through two leaflets, resulting in two distinct events.
• Coupled bilayers exhibited single-step tip penetration.
• DFS experiments at varying temperatures and spring constants allowed better comparison with theoretical models.

Conclusions:

• Interleaflet coupling is a critical factor governing the mechanical response of lipid bilayers.
• AFM and DFS provide valuable insights into membrane mechanics and protein-membrane interactions.
• The study offers improved methods for comparing experimental membrane mechanics data with theoretical predictions.