Programable and Spatially Conforming Assembly of Engineered Living Materials Onto Electrodes via Redox

Area of Science:

• Biomaterials Engineering
• Bioelectronics
• Tissue Engineering

Background:

• Hydrogel fabrication often lacks precise spatial control.
• Integrating biological components with electronic devices requires advanced assembly methods.
• Existing methods struggle with high cell viability during assembly.

Purpose of the Study:

• To develop an electrobiofabrication technique for precise cell/gel assembly on electrodes.
• To investigate the correlation between fabrication parameters and hydrogel properties.
• To demonstrate the versatility of the method for various applications.

Main Methods:

• Oxidative crosslinking of thiolated polyethylene glycol (PEG) using a ferrocene redox mediator and applied electrical charge.
• Controlled hydrogel formation defined by electrode geometry and applied potential duration.
• Gravity-mediated layering and electroassembly onto diverse conductive materials.

Main Results:

• Achieved precise, electrode-defined cell/gel formations with near 100% cell viability (E. coli).
• Demonstrated strong positive correlations between mediator concentration, charge, cell density, and gel thickness/density.
• Successfully electroassembled hydrogels onto arbitrarily shaped conductive surfaces.

Conclusions:

• The electrobiofabrication method offers electronic control over cell-laden hydrogel assembly.
• This technique enables new possibilities for cell-device interactions, biosensing, and electrogenetics.
• The developed methodology facilitates programmed assembly for advanced bioelectronic applications.