Polysaccharide Hydrogels cross-linked via Thermo-Responsive Peptide-Dendrimers

Yulia Shmidov, Ben Gurion University, Beer Sheva, Israel
Mingjun Zhou, Virginia Polytechnic Institute, Virginia, USA
John B. Matson, Virginia Polytechnic Institute, Virginia, USA
Ronit Bitton, Ben Gurion University, Beer Sheva, Israel

Elastin-like peptides (ELPs)  are molecules that have been used to confer thermoresponsive characteristics onto various materials, however to this point mostly linear ELPs have been studied. Dendritic and other highly branched structures are important in biomaterials because they are often used as crosslinkers to make polymeric hydrogels. Moreover, their topological features may lead to useful properties in biomaterials, including substantially improved resistance to proteolysis of branched peptides compared to linear ones.

Here we present a systematic investigation of a class of dendritic ELPs based on the GLPGL pentamer repeat unit.  

The effect of peptide topology (e.g. peptide length, generation no. etc) on the transition temperature (T_t) was examined, using CD measurement, turbidity test, cryo-TEM and SAXS. Our findings support a phase transition model that consists of three neighboring processes: a secondary structure transition, related to intramolecular interactions thus not effected by the peptide topology; Followed by continuous nanopartical formation  associated with intermolecular interactions and coacervation, The temperature in which both occur depend on  the dendrimer’s coree length and its generation number.

Lastly, the potential of these dendritic ELPs as building blocks for thermoresponsive gels   is demonstrated by utilizing them as crosslinkers for   hyaluronic acid using carbodiimide chemistry.