Lipid bilayer disruption induced by amphiphilic Janus nanoparticles: the non-monotonic effect of charged lipids

In this study, we report the complex effects of charged lipids on the interaction between amphiphilic Janus nanoparticles and lipid bilayers. Janus nanoparticles are cationic on one hemisphere and hydrophobic on the other. We show that the nanoparticles, beyond threshold concentrations, induce holes in both cationic and anionic lipid bilayers mainly driven by hydrophobic interactions. However, the formation of these defects is non-monotonically dependent on ionic lipid composition. The electrostatic attraction between the particles and anionic lipid bilayers enhances particle adsorption and lowers the particle concentration threshold for defect initiation, but leads to more localized membrane disruption. Electrostatic repulsion leads to reduced particle adsorption on cationic bilayers and extensive defect formation that peaks at intermediate contents of cationic lipids. This study elucidates the significant role lipid composition plays in influencing how amphiphilic Janus nanoparticles interact with and perturb lipid membranes.