Multidimensional assembly of s-layer proteins on mobility-controlled polyelectrolyte multilayers

Polyelectrolyte multilayers have been vastly utilized as an assembling platform for various biomaterials because of their soft and charged surface characteristics, analogous to biomembrane systems. In particular, polyelectrolyte chains with high self-diffusivity can effectively transfer the surface mobility to the assembling biomolecular species, facilitating the ordered self-assembly. Herein, highly diffusional cationic polyelectrolyte chains of linear polyethylenimine are employed to induce direct binding with negatively charged bacterial surface layer proteins, which eventually lead to large-scale two-dimensional crystals. Notably, at the elevated incubation temperature, a transitory intermediate of one-dimensional chain structure is observed. We reveal that this one-dimensional intermediate is a stable precursor toward two-dimensional crystal arrays.