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Atomic Force Microscopy Imaging and Force Spectroscopy of Supported Lipid Bilayers
Published on: July 22, 2015
Critical point fluctuations in supported lipid membranes
Simon D Connell1, George Heath, Peter D Olmsted
1School of Physics and Astronomy, University of Leeds, Leeds, UK. s.d.a.connell@leeds.ac.uk
Faraday Discussions
|June 29, 2013
Summary
Supported lipid bilayers exhibit critical phenomena observable with atomic force microscopy (AFM). This study provides direct evidence of nanoscale domains in critical regions, potentially explaining lipid raft structures in cell membranes.
Area of Science:
- Biophysics
- Materials Science
- Surface Science
Background:
- Supported lipid bilayers are model systems for cell membranes.
- Understanding critical phenomena in these bilayers is crucial for cell membrane research.
- Atomic force microscopy (AFM) offers high-resolution imaging capabilities.
Purpose of the Study:
- To investigate critical phenomena in supported lipid bilayers using AFM.
- To characterize nanoscale domains and their relation to lipid raft structures.
- To determine the applicability of the 2D Ising model to lipid bilayer phase transitions.
Main Methods:
- Utilizing atomic force microscopy (AFM) with precise temperature control.
- Measuring and calculating phase diagrams for the L(d)-L(o) phase region.
- Analyzing compositional fluctuations using spatial correlation functions.
- Observing domain boundary roughening and density fluctuations below the critical temperature (T(c)).
Main Results:
- Critical phenomena in supported lipid bilayers were observed using AFM.
- The phase transition aligns with the 2D Ising model, indicating a critical transition.
- Nanoscale domains (10-100 nm) exhibiting critical fluctuations were identified above T(c) into the biological temperature range.
- Domain boundary roughening and smaller-scale density fluctuations were detected below T(c).
Conclusions:
- Supported lipid bilayers display critical phenomena consistent with the 2D Ising model.
- The identified critically fluctuating nanoscale domains are strong candidates for lipid raft structures in cell membranes.
- AFM with precise temperature control is a powerful tool for studying critical phenomena in lipid bilayers.
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