Preparation of heat-induced artificial collagen gels based on collagen-mimetic dendrimers

Collagen, a major component of the extracellular matrix, contains Gly-Pro-Hyp repeats that form a hydrogel. In this study, artificial collagen-mimetic materials were designed. Synthetic dendritic macromolecules were fully modified with (Pro-Hyp-Gly) _n and named collagen-mimetic dendrimers. A collagen-like triple helical structure was observed by circular dichroism spectrometry, with an efficiency that depended on the peptide length. A (Pro-Hyp-Gly) ₁₀-modified dendrimer exhibited the most efficient triple helix formation. Thermal stability was enhanced by clustering at the surface of the dendrimer. The (Pro-Hyp-Gly) ₁₀-modified dendrimer was assembled by heating and the assembly was affected by temperature, time and concentration. Hydrogels based on the (Pro-Hyp-Gly) ₁₀-modified dendrimer, but not on the peptide itself, were successfully prepared by heating. The sol-gel transition behavior was similar to natural collagen but not gelatin, which is thermally denatured collagen. Dynamic rheological analysis showed that the sol-gel transition temperature and the strength depended on the concentration. Thus, the collagen-mimetic dendrimer incorporating (Pro-Hyp-Gly) ₁₀ is an injectable and controllable artificial collagen gel.