Alfredo Alexander-Katz

Professor Alfredo Alexander-Katz, MIT.  "Transmembrane Nanoparticles." Student-hosted seminar.

Designing nanomaterials that can mimic biological systems (e.g. proteins or viruses) is one of the major challenges in the field of nanomedicine and nanobiotechnology. In particular, creating synthetic soluble nanoparticles (NPs) that can fuse reversibly (or irreversibly) with the cellular membrane and behave as membrane proteins could allow us to insert and translocate materials across membranes, signal specific conditions, and even control the shape of cells or organelles. In this talk I will present our theoretical and computational work on designing transmembrane nanoparticles, which are a class of nanoparticles composed of a metallic core protected by a ligand shell with hydrophilic groups at the ends. Recently, it was discovered that these particles can insert themselves spontaneously into a lipid bilayer resembling their biological counterparts: transmembrane fusion proteins or cell penetrating peptides.  By using a combination of analytical theory and simulations we find that the key to bilayer complexation is the rearrangement of ligands by bending to maximize hydrophobic matching and minimize charge exposure. Our results also indicate that one can design nanoparticles to fuse selectively with different lipids, and in principle be able to sculpt the bilayer. Finally, these results improve our understanding on how to interface synthetic and biologica materials and enable the design of nanoparticles for drug delivery and biosensing applications.