Detergent solubilization of lipid bilayers: a balance of driving forces

Although detergents are routine tools in biomembrane research, their use remains empirical. We propose that solubilization is the result of a balance between two parameters: (i) the energy associated with bending of phospholipid monolayers into a curved micellar surface, and (ii) the energy associated with filling the void in the center of the resultant mixed micelle. In this review, we show that reliable data on the phase boundaries, and their dependence on various conditions, are consistent with this hypothesis, even if the data might have been interpreted differently. Although most of the experimental data discussed here were obtained with the non-ionic detergent Triton X-100, the conclusions should be applicable to a wide variety of detergents.