Measuring the bending modulus of lipid bilayers with cholesterol

The effect of cholesterol on the bending modulus of DOPC lipid bilayers has become a controversial topic that has implications for methods of measuring the bending modulus. Recent results using neutron spin echo and nuclear magnetic resonance relaxation methods that involve linear transport properties have conflicted with earlier results from purely equilibrium experiments that do not involve linear transport properties. A general discussion indicates how one can be misled by data obtained by methods that involve linear transport properties. It is then shown specifically how the recent neutron spin echo results can be interpreted to agree with the earlier purely equilibrium experimental results, thereby resolving that conflict. Regarding the nuclear magnetic resonance relaxation method, it is noted that current interpretation of the data is unclear regarding the identity of the modulus that is involved, and an alternative interpretation is explored that does not disagree with the results of the equilibrium experiments.

Automated summary

The impact of cholesterol on the bending modulus of DOPC lipid bilayers and the controversy surrounding it have implications for measurement methods. Recent studies conflict with earlier experiments, with linear transport methods potentially leading to misleading interpretations. By reinterpreting recent neutron spin echo results, the conflict may be resolved, while the uncertainty in interpreting nuclear magnetic resonance relaxation data suggests the need for exploring alternative explanations that align with equilibrium experiments.