Controlling the morphology of metal-triggered collagen peptide assemblies through ligand alteration

A number of methods have been explored to promote the higher order assembly of collagen peptide triple helices. In one case, NCoH, a complex hierarchical metal-promoted assembly was observed to form micron-scaled florettes with a ruffled surface topology at the nanoscale. In an effort to elucidate the role of the ligands in this collagen peptide assemblage, we reduced the number of carboxylates within the N-terminal ligand to produce a new peptide, ICoH. A striking difference in the morphology of the metal-triggered material was observed with ICoH, with stacked arrays of nanofibrils predominating. As the peptide to metal ion ratio was increased, the length of the stacks of fibrils was also observed to increase. These data demonstrate that a significantly less complex assembly process occurs with the removal of a single carboxylate moiety from the metal binding ligand at the termini of the collagen peptide.