Peptide-Based Soft Hydrogels Modified with Gadolinium Complexes as MRI Contrast Agents.

Area of Science:

• Supramolecular chemistry
• Nanomedicine
• Biomaterials science

Background:

• Poly-aromatic peptides self-assemble into diverse nanostructures like fibers and hydrogels.
• These biocompatible peptide nanostructures are promising for tissue engineering, drug delivery, bioimaging, and biosensors.
• Magnetic Resonance Imaging (MRI) requires effective diagnostic agents for enhanced visualization.

Purpose of the Study:

• To synthesize and characterize novel supramolecular diagnostic agents for MRI.
• To evaluate the self-assembly, structural properties, and relaxometric behavior of new peptide conjugates.
• To assess the potential of these agents in nanomedicine and diagnostic imaging.

Main Methods:

• Synthesis of DTPA(Gd)-PEG8-(FY)3 and DOTA(Gd)-PEG8-(FY)3 peptide conjugates.
• Characterization of self-assembly into supramolecular aggregates and hydrogels.
• Relaxometric measurements to determine relaxivity values.
• In vitro cytotoxicity assays.

Main Results:

• The peptide conjugates self-assembled into stable hydrogels at 1.0% wt concentration.
• Structural characterization confirmed the formation of beta-sheet structures with antiparallel beta-strands.
• The nanostructures exhibited high relaxivity values (approximately 12 mM⁻¹·s⁻¹ at 20 MHz).
• Very low in vitro cytotoxicity was observed.

Conclusions:

• Novel Gd-complexed peptide conjugates form self-supporting hydrogels with potential as MRI diagnostic agents.
• The self-assembled nanostructures maintain structural integrity and exhibit excellent relaxivity.
• These findings suggest promising applications in MRI-based diagnostics and nanomedicine.