Fuel-Driven and Enzyme-Regulated Redox-Responsive Supramolecular Hydrogels

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Biomaterials Engineering

Background:

• Chemical reaction networks (CRNs) in hydrogels enable responsive materials.
• Supramolecular crosslinks offer tunable material properties.
• Enzyme-driven redox reactions are key to material function.

Purpose of the Study:

• To develop self-regulating hydrogels using host-guest supramolecular crosslinks.
• To investigate the transition from responsive to self-regulating behavior.
• To explore the hydrogel's potential as a glucose sensor.

Main Methods:

• Incorporation of β-cyclodextrin (CD) and ferrocene (Fc) host-guest pairs.
• Utilizing enzyme-fuel couples: horse radish peroxidase (HRP)-H₂O₂ and glucose oxidase (GOx)-d-glucose.
• Employing UV/Vis spectroscopy, rheology, and kinetic modeling.

Main Results:

• Tuning d-glucose concentration shifted hydrogel behavior from responsive to self-regulating.
• Self-regulation emerged due to oxidation fuel generation via GOx[FADH₂].
• Programmable negative feedback was observed, including adaptable elastic modulus.

Conclusions:

• Hydrogels with CD-Fc crosslinks exhibit tunable self-regulating properties.
• The system demonstrates out-of-equilibrium behavior driven by enzymatic reactions.
• The adaptable hydrogel shows promise for glucose sensing applications.