Polysaccharide Hydrogels Cross-Linked via Peptide Dendrimers

Dendritic and other highly branched structures are of importance in biomaterials since their topological features may lead to useful properties, including substantially improved resistance to proteolysis of branched peptides compared to linear ones. As crosslinkers, dendrimers offer the advantage of versatility in terms of number and chemical composition of surface functionalities; a versatility that can be translated to gels with easily tunable structure and properties.

Here we present polysaccharides-dendrimer gels composed of hyaluronic acid (HA) and elastin-like peptide (ELP) dendrimers, in which the peptide dendrimer is acting as a crosslinker.

As ELPs have been shown to confer thermos-responsive characteristics onto various materials we first explored the thermal behavior of elastin-like peptide (ELP) dendrimers, up to 3 generations and 155 amino acid residues. We found that the lower critical solution temperature (LCST) phenomenon, which is commonly observed in linear ELPs remained with the dendrimer topology. In addition, the branching structure in dendrimers changed the LCST compared to their linear counterparts, probably due to the steric effect during the self-assembly. Moreover, combining TEM, DSC and SAXS, we proved that the size change of the aggregates was a gradual process over a wide temperature range, instead of an abrupt leap at the LCST. Secondly, we investigated the effect of the ELP dendrimer’s characteristics on the mechanical properties and structure of three ELP dendrimer-based HA hydrogels.