Additively Manufactured 3D Micro-bioelectrodes for Enhanced Bioelectrocatalytic Operation

Area of Science:

• Materials Science
• Bioelectronics
• Additive Manufacturing

Background:

• Miniaturization of enzyme-based bioelectronics requires 3D microstructured electrodes, challenging for conventional methods.
• Additive manufacturing and electroless plating offer routes to 3D conductive microarchitectures but face adhesion issues.
• Interfacial delamination compromises device reliability and performance in bioelectronic applications.

Purpose of the Study:

• To develop a robust method for creating highly conductive and strongly adhered metal layers on 3D printed polymer microstructures.
• To overcome the challenge of interfacial delamination in 3D microelectrodes for enhanced bioelectronic device reliability.
• To demonstrate the improved performance of bioelectronic devices utilizing these novel 3D microelectrodes.

Main Methods:

• Synthesized multifunctional acrylate monomers with alkoxysilane groups via thiol-Michael addition.
• Utilized projection micro-stereolithography (PμSLA) for 3D printing, preserving alkoxysilane functionality.
• Applied a post-functionalization sol-gel process to create an interfacial adhesion layer with thiol groups for enhanced gold binding.

Main Results:

• Achieved excellent conductivity (2.2 × 10^7 S/m, 53% of bulk gold) with strong gold-polymer adhesion, verified by sonication and tape tests.
• Demonstrated a 10-fold increase in current density (2.5 μA/cm^2 at 0.35 V) in an enzymatic biofuel cell using a 3D lattice microelectrode.
• Successfully created robust, high-surface-area 3D conductive microelectrodes suitable for bioelectronic applications.

Conclusions:

• The developed interfacial adhesion layer method significantly enhances the conductivity and reliability of 3D printed microelectrodes.
• This technique enables robust metal-polymer interfaces, crucial for the long-term performance of bioelectronic devices.
• The improved 3D microelectrodes show great promise for advancing enzymatic biofuel cell technology and other bioelectronic applications.