Dendritic Elastin-like Peptides: The Effect of Branching on Thermoresponsiveness
Yotam Navon, Mingjun Zhou, John B. Matson, Ronit Bitton
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 (Tt) 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 Tt 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.
Circular dichroism, Thermodynamics, Secondary structure, Materials