Fmoc-Phe : Fmoc-Leu supramolecular hydrogels with adaptive antibacterial activity

Area of Science:

• Biomaterials Science
• Supramolecular Chemistry
• Antimicrobial Materials

Background:

• Antimicrobial resistance is a growing global health threat.
• Peptide-based hydrogels show promise as adaptive soft materials with antibacterial activity.
• Fmoc-phenylalanine (Fmoc-Phe) and Fmoc-leucine (Fmoc-Leu) are known gelators with inherent antimicrobial properties.

Purpose of the Study:

• To investigate the synergistic effects of combining Fmoc-Phe and Fmoc-Leu into a multicomponent hydrogel system.
• To demonstrate the ability to tune the physical and antimicrobial properties of the hydrogel by varying the Fmoc-Phe:Fmoc-Leu ratio.
• To establish a structure-activity relationship for designing peptide-based hydrogels with tailored functionalities.

Main Methods:

• Synthesis and characterization of multicomponent Fmoc-Phe/Fmoc-Leu hydrogels with varying component ratios.
• Rheological measurements to assess viscoelastic and self-healing properties.
• Spectroscopic analyses (e.g., FTIR, CD) to study self-assembly and β-sheet organization.
• Antibacterial assays against Gram-positive and Gram-negative bacterial strains.

Main Results:

• The Fmoc-Phe:Fmoc-Leu ratio significantly influences hydrogel self-assembly, gelation efficiency, and physical properties (viscoelasticity, self-healing, thermoresponsiveness).
• β-sheet organization is maintained across different ratios, while system stability correlates with the proportion of unassembled gelator.
• Hydrogel formulations exhibit tunable antimicrobial activity, with Gram-positive bacteria showing higher susceptibility.
• A clear structure-activity relationship was identified, linking composition to material and antimicrobial performance.

Conclusions:

• Compositional tuning of Fmoc-Phe/Fmoc-Leu hydrogels is a simple yet effective strategy for developing adaptive soft materials.
• These peptide-based hydrogels offer tailorable physical, material, and antimicrobial properties for addressing challenges like antimicrobial resistance.
• The study provides a framework for designing advanced peptide hydrogels with specific functionalities for biomedical applications.