Drawing with Iron on a Gel Containing a Supramolecular Siderophore

Area of Science:

• Supramolecular chemistry
• Materials science
• Biomaterials

Background:

• Guanosine derivatives can self-assemble into hydrogels.
• Hydroxamic acid groups offer pH-responsiveness and metal-chelating properties.
• G-quartet hydrogels have potential in various advanced applications.

Purpose of the Study:

• To develop a novel hydrogel with tunable properties using guanosine and a hydroxamic acid derivative.
• To investigate the pH-responsive and metal-chelating capabilities of the synthesized hydrogel.
• To explore the potential for patterning and creating functional materials using this hydrogel system.

Main Methods:

• Synthesis of guanosine-5'-hydroxamic acid.
• Hydrogel formation by mixing with guanosine and KCl.
• pH-dependent binding of thiazole orange.
• Complexation with Fe³⁺ to form colored complexes.
• Surface patterning using FeCl₃ via manual and 3D printing methods.
• Assessment of pattern stability and erasability.

Main Results:

• Guanosine-5'-hydroxamic acid forms stable hydrogels with guanosine and KCl.
• The hydrogel exhibits pH-dependent binding of thiazole orange, indicated by fluorescence changes.
• The hydroxamic acid moiety acts as a supramolecular siderophore, forming red complexes with Fe³⁺.
• Patterning of the hydrogel surface with FeCl₃ is achieved instantly, is visually apparent, and can be reversed with vitamin C.
• The resulting hydrogel is robust, moldable, and stable in various conditions.

Conclusions:

• A novel, multifunctional hydrogel combining G-quartet self-assembly and siderophore-metal complexation has been created.
• The hydrogel's pH-responsiveness and metal-binding capacity enable dynamic functionalization and patterning.
• This material demonstrates potential for applications in sensing, responsive materials, and 3D-printable constructs.