Presentation Information
[P03-333]Metal Ion–Induced Formation of Tunable Hydrogels from Unmodified Short Peptides with Controlled Drug Release
○KENTA FUKUMOTO1, Asuka Inada1, Tatsuya Oshima1 (1. Miyazaki Univ. (Japan))
Keywords:
peptide,hydrogel,nanomaterial,supramolecular,metal complex
[Purpose]
In recent years, amino acid-based materials have attracted significant attention for the development of novel functional materials. Owing to their biocompatibility and structural tunability, they are considered promising candidates for supramolecular materials. However, studies on unmodified short peptides—capable of fully exploiting the intrinsic properties of amino acids while maintaining synthetic simplicity—remain limited. In this study, we focus on the interactions between unmodified short peptides and metal ions to investigate their potential for hydrogel formation via self-assembly. Furthermore, the physicochemical properties of the resulting hydrogels were evaluated to explore their applicability as drug delivery materials.
[Method]
Unmodified tetrapeptides containing histidine (His) and phenylalanine (Phe) were synthesized using Fmoc-based solid-phase peptide synthesis. Isoleucine (Ile) was employed as a non-aromatic reference residue for comparison with Phe. The synthesized peptides were mixed with aqueous copper chloride solutions to evaluate their gelation behavior. The supramolecular structures of the resulting hydrogels were characterized using scanning electron microscopy (SEM), circular dichroism (CD) spectroscopy, and FT-IR spectroscopy. Additionally, their potential as drug delivery systems was assessed through model drug release experiments.
[Results]
Upon the addition of copper(II) chloride, all peptides formed hydrogels even at relatively low concentrations. The gelation ability was strongly dependent on the number of Phe residues. SEM observations revealed the formation of characteristic fibrous network structures. Furthermore, CD and FT-IR analyses indicated that Phe residues effectively promote the formation of β-sheet-rich structures. In drug release experiments, the release profiles varied depending on both the number of Phe residues and pH, demonstrating the potential of these materials as tunable drug delivery systems.
[Consideration]
ConsiderationThe observed gelation at low concentrations, together with the changes in FT-IR spectra, suggests that coordination interactions between copper ions and peptides effectively promote self-assembly. In sequences lacking Phe residues, β-sheet formation was not observed, indicating that aromatic interactions involving Phe side chains play a crucial role in structural organization. Moreover, the gelation ability appears to change beyond a certain threshold number of Phe residues, which is consistent with the trends observed in drug release behavior.
[Conclusion]
ConclusionIn this study, peptide hydrogels based on unmodified short peptides were successfully developed and systematically evaluated. The results clearly demonstrated that the physicochemical properties of hydrogels are strongly dependent on the number of Phe residues. Furthermore, the hydrogels exhibited pH-responsive behavior and showed potential as drug delivery materials. These findings highlight that such peptide-based hydrogels can serve as a versatile platform for designing novel functional materials with tunable properties tailored to specific applications.
In recent years, amino acid-based materials have attracted significant attention for the development of novel functional materials. Owing to their biocompatibility and structural tunability, they are considered promising candidates for supramolecular materials. However, studies on unmodified short peptides—capable of fully exploiting the intrinsic properties of amino acids while maintaining synthetic simplicity—remain limited. In this study, we focus on the interactions between unmodified short peptides and metal ions to investigate their potential for hydrogel formation via self-assembly. Furthermore, the physicochemical properties of the resulting hydrogels were evaluated to explore their applicability as drug delivery materials.
[Method]
Unmodified tetrapeptides containing histidine (His) and phenylalanine (Phe) were synthesized using Fmoc-based solid-phase peptide synthesis. Isoleucine (Ile) was employed as a non-aromatic reference residue for comparison with Phe. The synthesized peptides were mixed with aqueous copper chloride solutions to evaluate their gelation behavior. The supramolecular structures of the resulting hydrogels were characterized using scanning electron microscopy (SEM), circular dichroism (CD) spectroscopy, and FT-IR spectroscopy. Additionally, their potential as drug delivery systems was assessed through model drug release experiments.
[Results]
Upon the addition of copper(II) chloride, all peptides formed hydrogels even at relatively low concentrations. The gelation ability was strongly dependent on the number of Phe residues. SEM observations revealed the formation of characteristic fibrous network structures. Furthermore, CD and FT-IR analyses indicated that Phe residues effectively promote the formation of β-sheet-rich structures. In drug release experiments, the release profiles varied depending on both the number of Phe residues and pH, demonstrating the potential of these materials as tunable drug delivery systems.
[Consideration]
ConsiderationThe observed gelation at low concentrations, together with the changes in FT-IR spectra, suggests that coordination interactions between copper ions and peptides effectively promote self-assembly. In sequences lacking Phe residues, β-sheet formation was not observed, indicating that aromatic interactions involving Phe side chains play a crucial role in structural organization. Moreover, the gelation ability appears to change beyond a certain threshold number of Phe residues, which is consistent with the trends observed in drug release behavior.
[Conclusion]
ConclusionIn this study, peptide hydrogels based on unmodified short peptides were successfully developed and systematically evaluated. The results clearly demonstrated that the physicochemical properties of hydrogels are strongly dependent on the number of Phe residues. Furthermore, the hydrogels exhibited pH-responsive behavior and showed potential as drug delivery materials. These findings highlight that such peptide-based hydrogels can serve as a versatile platform for designing novel functional materials with tunable properties tailored to specific applications.
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