Design of lipidic platforms anchored within nanometric cavities by peptide hooks

Stable confinement of liposomes into arrays of hybrid polymer/Au nanocavities was achieved by peptide hooks covalently linked to the Au floor. The peptide hooks are thiolated analogs of trichogin GA IV (SSTrGA),a well-­‐known broadband antimicrobial peptide with high affinity for lipids, functionalized at the N-­‐terminus with an α-­lipoic group for linking to Au substrates. SSTrGA promoted the opening of liposomes, giving rise to formation of a lipid bilayer paving the nanocavity. To this aim, a patterned nanoporous surface was prepared by using a colloidal solution of monodisperse silica nanospheres that formed a cubic close-­‐packed array onto the Au substrate. The nanosphere array was then processed by spin coating a poly(methylmethacrylate) solution, followed by selective removal of the silica nanoparticles, yielding an array of hybrid nanocavities formed by poly(methylmethacrylate) walls and paved by an Au floor. The Au layer was therefore modified by covalent linkage of SSTrGA, forming a densely packed self-­‐assembled monolayer on the Au floor of the nanowells, as demonstrated by cyclic voltammetry experiments. Atomic force microscopy and quartz crystal microbalance with dissipation monitoring were applied to study the inclusion of the peptide/liposome system into the hybrid nanocavities and formation of the lipid bilayer inside them. This system could be usefully exploited as a patterned biomimetic environment able to host membrane proteins or lipophilic enzymes for the development of new bioinspired functional materials and for biosensing based on ligand-protein recognition.