Charged Nanoparticles Interacting with Giant Vesicles Fabricated from Inverted-Headgroup Lipids

The surface chemistry of the cell membrane plays an important role in how cells interact with particulate species. These interactions are dictated in large part by lipid headgroup charge. To investigate the nature of electrostatic interactions between lipid bilayers and nanoparticles in solution, we investigated nanoparticles interacting with DOPC (1,2-dioleoyl-glycero-3-phosphocholine) and DOCP lipids, in which the zwitterionic head group was inverted from its natural configuration in DOPC.

These interactions were investigated by fabricating giant unilamellar vesicles (GUVs) with DOPC lipids and DOCP lipids respectively, and introducing nanoparticles to suspensions of both. In the presence of charged polystyrene nanoparticles, GUVs displayed various degree of deformation depending on the charge sign and size of the nanoparticles. These differences illuminate how the relative positions of phosphate group and choline group in the headgroup determine the interaction with charged particles. This work provides fundamental insights regarding the nature of this interaction, which has implications for the development of new drug delivery vehicles as well as understanding the environmental toxicity of nanomaterials.