pH-Responsive Biocompatible Supramolecular Peptide Hydrogel.

Area of Science:

• Biomaterials Science
• Supramolecular Chemistry
• Biomedical Engineering

Background:

• Peptide-based hydrogels offer tunable properties for biomedical uses.
• Stimuli-responsive hydrogels are crucial for controlled drug delivery and tissue engineering.
• Biocompatibility and precise self-assembly are key requirements for advanced biomaterials.

Purpose of the Study:

• To report the pH-responsive self-assembly and gelation of a novel amphiphilic peptide, PEP-1.
• To characterize the structural and mechanical properties of the PEP-1 hydrogel.
• To evaluate the stimuli-responsive release capabilities and biocompatibility of the PEP-1 hydrogel.

Main Methods:

• Synthesis of the octa-peptide PEP-1 using solid-phase synthesis.
• Characterization of self-assembly and gelation via rheology and microscopy.
• Structural analysis using circular dichroism, FTIR, and Thioflavin T assay.
• Assessment of guest molecule release and cell viability (MTT assay).

Main Results:

• PEP-1 undergoes spontaneous gelation at pH 7.4, forming a β-sheet rich fibrillar network with high yield stress (88.0 Pa) and thermal stability (84 °C).
• The hydrogel disassembles at acidic or alkaline pH due to ionizable Asp and Lys residues.
• Calcein entrapment and selective release at acidic pH were demonstrated.
• MTT assay confirmed excellent biocompatibility, with nearly 100% cell viability at 2.0 mg/mL PEP-1.

Conclusions:

• PEP-1 forms a stable, biocompatible, pH-responsive peptide hydrogel.
• The pH-triggered disassembly enables controlled release of encapsulated molecules.
• PEP-1 hydrogels show significant potential for advanced biomedical applications, including drug delivery and regenerative medicine.