Multi-scale characterization of thermoresponsive dendritic elastin-like peptides

[Display omitted] •Dendrimers based on ELP were synthesized with Mw in excess of 14,000Da.•The dendrimer were characterized with techniques typically reserved for polymers.•A pre-coacervation phase was observed upon heating. Elastin like peptides (ELPs)—polypeptides based on the protein elastin—are...

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Bibliographic Details
Published in:Colloids and surfaces, B, Biointerfaces B, Biointerfaces, 2017-05, Vol.153, p.141-151
Main Authors: Zhou, Mingjun, Shmidov, Yulia, Matson, John B., Bitton, Ronit
Format: Article
Language:English
Subjects:
Coacervation
Cryo-TEM
Dendrimer
Dendrimers - chemistry
Elastin - chemistry
LCST
Molecular Structure
Peptides - chemistry
SAXS
Temperature
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Summary:[Display omitted] •Dendrimers based on ELP were synthesized with Mw in excess of 14,000Da.•The dendrimer were characterized with techniques typically reserved for polymers.•A pre-coacervation phase was observed upon heating. Elastin like peptides (ELPs)—polypeptides based on the protein elastin—are used widely as thermoresponsive components in biomaterials due to the presence of a sharp soluble-to‐insoluble phase change at a characteristic transition temperature (Tt). While linear ELPs have been thoroughly studied, few investigations into branched ELPs have been carried out. Using lysine amino acids as branching and terminal units with 1–3 pentameric repeats between each branch, ELP dendrimers were prepared by solid-phase peptide synthesis with molecular weights as high as 14kDa. A conformation change from random coil to β-turn upon heating through the Tt, typical of ELPs, was observed by circular dichroism spectroscopy for all peptides. The high molecular weights of these peptides enabled the use of characterization techniques typically reserved for polymers. Variable-temperature small-angle X-ray scattering measurements in dilute solution revealed an increase in size and fractal dimension upon heating, even well below the Tt. These results were corroborated by cryogenic transmission electron microscopy, which confirmed the presence of aggregates below the Tt, and micro differential scanning calorimetry, which showed a broad endothermic peak below the Tt. These results collectively indicate the presence of a pre-coacervation step in the phase transition of ELP dendrimers.
ISSN:0927-7765
1873-4367
DOI:10.1016/j.colsurfb.2017.02.014