Construction of ferritin hydrogels utilizing subunit-subunit interactions

Area of Science:

• Biomaterials Science
• Protein Engineering
• Nanotechnology

Background:

• Proteins can self-assemble into nanostructures with unique functional properties.
• Ferritin is a spherical protein known for its iron storage capacity.
• Developing novel protein-based biomaterials is an active area of research.

Purpose of the Study:

• To investigate the potential of apoferritin to form hydrogels.
• To characterize the properties of apoferritin-based hydrogels.
• To evaluate the metal ion adsorption and desorption capabilities of these hydrogels.

Main Methods:

• Acid denaturation and neutralization of concentrated apoferritin solutions to form hydrogels.
• Atomic force microscopy (AFM) for mechanical property analysis (Young's modulus).
• Transmission electron microscopy (TEM) for structural analysis.
• Incubation with various metal ions (Fe3+, Co2+, Cu2+, Ni2+) and chelating agents (EDTA) to assess adsorption/desorption.

Main Results:

• Apoferritin readily formed hydrogels with approximately 80% water content.
• The hydrogel exhibited a Young's modulus of 20.4 ± 12.1 kPa, indicating relative stiffness.
• TEM revealed a fibrous network structure within the hydrogel.
• The hydrogel demonstrated selective adsorption of Fe3+ ions, retaining ferritin's iron-binding characteristic, and could adsorb/desorb other metal ions like Co2+ and Cu2+.

Conclusions:

• Apoferritin can be utilized to create functional hydrogels through a simple denaturation-neutralization process.
• These apoferritin hydrogels possess mechanical integrity and a fibrous structure.
• The hydrogels exhibit controllable metal ion adsorption and desorption, particularly for Fe3+, highlighting their potential as biomaterials for ion management.