Patchy peptide particles for pH-responsive assembly into liquid crystals or lattices

Programmable control of protein or colloidal nanoparticle self-assembly into targeted nanostructures, while maintaining stability across extreme pH conditions, remains a major challenge. We designed coiled-coil bundlemer peptide nanoparticles that form ordered, hierarchical materials across an unusually broad pH range (1, 7, and 14) dependent on patchy surface charge display. Nematic liquid crystal formation was observed at low concentration (~0.5 to 4 weight %) at pH 1 and pH 14, whereas higher concentration at pH 1 yielded hexagonal columnar phases. At neutral pH, the same patchy nanoparticles assembled into ordered lattices through electrostatic complexation. Molecular dynamics simulations revealed end-to-end particle stacking underlying all phases. Coiled coils with identical amino acid composition but lacking designed charge patches displayed no ordered assembly, demonstrating the importance of programmable electrostatic interactions with protein-like specificity of spatial display.