Effects of external force fields on peptide self-assembly and biomimetic silica synthesis

This study investigated the influence of physical parameters on the dynamic self-assembly of short peptide amphiphiles (A(6)K and V6K) and the peptide-mediated silica morphologies by applying external force fields (electric and flow fields). Diverse self-assembled structures (nanofibers, nanorods, or lamellar stacks) can be obtained depending on field intensities and molecular architectures. Although the trend in the structural transitions observed from the electrostatic stimulation differed from that obtained in flow field, the common features indicate that the formed structures exhibit a higher extent of end-to-end merging or lateral association. These self-assembled peptide-based nanostructures then were used as organic templates to tailor silica deposition. It was found that the application of flow fields can stably produce fibril morphology. However, in the case of electric fields, different silica structures were obtained by using different systems. The silica morphologies directed by V6K peptide were transformed from fibrils to plate-like structures, and A(6)K peptide produced fibril silica materials. The difference may be attributed to different biomimetic conditions, including external forces, solubility of hydrophobic blocks, and intensity of peptide-silicate interactions. This understanding of the mechanism by which external fields affect the self-assembled amphiphilic peptide nanostructures and the silicification process allows us to manipulate the role of short amphiphilic peptides in silica formation in vitro. (C) 2014 Elsevier B.V. All rights reserved.