Shear-induced structural transitions of peptide amphiphile

A novel method to construct hierarchical supramolecular structures in the designed peptide amphiphile solution was introduced. By simply shaking the solution at a certain frequency, the viscosity of the solution dramatically increased due to the conformational transitions and the construction of worm-like micelles, eventually causing networking of the nano-fibers made of peptide amphiphiles. The result implies that the new peptide amphiphiles undergo "hierarchical multi-scale structural transitions" ranging from a molecular-scale conformational transition, through nano-scale fibril formations, to macro-scale gelation, all caused by mechanical shear at a certain frequency. The transition was measured by Dynamic Mechanical Analysis (DMA), Circular Dichroism (CD) and cryogenic Transmission Electron Microscopy (cryo-TEM).