Effect of β-motif, chain length and topology on polypeptide-templated mesoporous silicas through biomimetic mineralization

This study reports a simple process using vesicular assemblies formed by cationic, coil-sheet block copolypeptides as templates to fabricate mesoporous silicas in aqueous solutions without adding any organic solvent or adjusting pH. Connective silica/polypeptide composite nanoparticles were formed due to the change of the bilayer curvature as well as the shrinkage of the bilayers upon silica mineralization and mesoporous silicas were fabricated via replicating the hydrophobic, sheet-like segment. Mesoporous silicas with size between 3 ∼ 8 nm templated by linear poly(Z-_L-lysine)-block-poly(S-benzyl-L-cysteine) (Lys-b-(Bzl)Cys) assemblies exhibited much higher porosity than those templated by others. It could be mainly attributed to the differences in the self-assembled structures for linear and star-shaped polypeptides as well as in the hydrophobic strength exerted by the sheet-like block. The average pore size increased with the increment of Lys-b-(Bzl)Cys chain length, correlated to the sheet-like (Bzl)Cys domain size depending on the polypeptide chain length. This study signified that the differences in polypeptide topology, chain length and sheet-like segment have impact on their self-assembly and subsequently affect the ability of these self-assembled structures for silica replication.