The self-assembly of biomolecules is an important issue explored in biomedical, biophysical, and bio-material research. Being able to understand how and why certain peptides and proteins prefer to self-assemble into larger networks can help shed light on their biological properties. It has been well established that structure determines function, and being able to understand the structures of peptides and their relation to their respective hydrogels can lead to a comprehensive understanding of how and why the monomer to gelation phase transition occurs. Recently, numerous rather different peptides have emerged as gelators even though they have not been classified as such before. The two short unblocked peptides, GAG and GHG, have been shown to form supramolecular structures under different conditions. GAG forms crystalline fibrils in a 55%/45% mole fraction ethanol/water solution if the peptide concentration exceed 200 mM, while GHG has been shown to form fibrils in water with lengths of hundreds of μm long at neutral pH even in the centimolar region. Being able to optimize the gelation process for specific applications is something of high interest and sometimes difficult due to the nature of the peptide. We will present spectroscopic and rheological data and the respective analysis for the fibrillization process as well as for characterizing the transition from the solution to the gel phase. Using these techniques, we obtained phase diagrams that reveal how the stability (melting temperature) of GAG and GHG gels depends on pH, temperature, peptide concentration and in the case of GAG, the fraction of the ethanol co-solvent. Results from kinetic experiments reveal how both, self-assembly into fibrils as well as gelation evolve over time. These data allow for an accurate optimization of gelation and melting conditions, as required by different biotechnological applications of the gels.

Exploration and tunability of the aggregation and gelation process of tripeptides

254th National Meeting (2017)

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