Using small- and wide-angle X-ray scattering we checked the effect of ion valency and lipid tail saturation level (using fully saturated lipids, hybrid lipids - containing a saturated and an unsaturated tail - and unsaturated lipids) on the interactions between dipolar membranes. We focused on the differences between multivalent, polyvalent and monovalent ions, and on the balance between the ion-dipole interactions and the structural and entropic aspects of the membrane (Langmuir 2011a, 2011b). The combined effect of temperature and osmotic stress on the interactions between dipolar membranes was also studied (J. Phys. Chem. B 2012). We performed advanced data analysis (using our analysis program X+) and compared our findings with known theories.

We found that when the lipid tails are saturated, multivalent ions (like calcium ions) adsorb onto the lipid bilayer but only above a critical concentration, suggesting that calcium adsorption requires an initial nucleation phase (J. Phys. Chem. A 2016).

We have also shown that calcium ions, which initially adsorbed onto lipid membranes, were removed by increasing osmotic stress (Langmuir 2017).

This work provides a broad and deep understanding of ion - dipolar membranal structures under a consistent framework. It models biologically relevant interactions between cell membranes and various ions and the manner in which lipid structure controls those interactions. The ability to monitor these interactions creates a tool for probing more complex membranes and assemblies and forms the basis for controlling the interactions between dipolar membranes and charged proteins or biopolymers for encapsulation and delivery applications.