文摘
Elastin-like peptides (ELPs) have been used widely to confer thermoresponsive characteristics onto various materials, but to this point mostly linear ELPs have been studied. A class of linear and dendritic (branched) ELPs based on the GLPGL pentamer repeat unit was synthesized using an on-resin divergent strategy. The effect of peptide topology on the transition temperature (Tb>tb>) was examined using circular dichroism to study the peptide secondary structure transition and turbidity to measure the macroscopic phase transition (coacervation). Secondary structure transitions showed no dependence on topology, but a higher Tb>tb> was observed for dendritic peptides than for linear peptides with the same number of GLPGL repeats. The data support a phase transition model that consists of two neighboring processes: a secondary structure transition, related to intramolecular interactions, followed by coacervation, associated with intermolecular interactions.