Dual pH-responsive pseudopeptide: hydrogelation and self-assembly into single- and multi-walled nanotubes.

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Biomedical Engineering

Background:

• Hydrogels are crucial in drug delivery and tissue engineering.
• pH-responsive materials offer controlled release mechanisms.
• Pseudopeptides present novel alternatives to traditional peptides.

Purpose of the Study:

• To develop a pH-responsive ionizable pseudopeptide hydrogel.
• To investigate the pH-triggered self-assembly and nanostructure evolution.
• To explore the potential biomedical applications of the hydrogel.

Main Methods:

• Synthesis of a heterochiral tripeptide N-capped with vermellogen.
• pH-dependent self-assembly studies.
• Electron microscopy for nanostructure analysis.
• Rheological measurements for viscoelastic properties.
• Drug release and in vitro cytocompatibility assays.

Main Results:

• The pseudopeptide forms a pH-responsive hydrogel.
• Protonation of vermellogen initiates hydrogelation; peptide protonation tunes nanostructure.
• Self-assembly evolves from nanofibers to nanotubes with increasing C-terminal deprotonation.
• Nanostructured gels exhibit parallel β-sheets with vermellogen in a clockwise helical pattern.
• Controlled release of an anticancer drug and good in vitro cytocompatibility were demonstrated.

Conclusions:

• The ionizable pseudopeptide hydrogel exhibits tunable pH-responsiveness from molecular to macroscale.
• The self-assembly pathway from nanofibers to nanotubes is driven by specific interactions.
• The developed hydrogel shows promise for biomedical applications, including drug delivery.