Maximizing Charge Injection Limits of Iridium Oxide Electrodes with a Programmable Anodic Bias Circuit

Area of Science:

• Biomedical Engineering
• Neuroscience
• Materials Science

Background:

• Efficacious neural stimulation demands high charge injection capacity and minimal electrode polarization.
• Anodic bias application is a known method to improve charge injection for neural electrodes.
• Existing methods often require external components like potentiometers or voltage sources.

Purpose of the Study:

• To develop an embedded neurostimulator system with digitally controlled anodic bias.
• To quantify the impact of anodic bias on charge injection capacity and current intensity.
• To evaluate the electrochemical safety of the applied bias potentials.

Main Methods:

• Development of an embedded neurostimulator with digital bias control.
• Electrochemical characterization of iridium oxide microelectrodes in phosphate-buffered saline.
• Comparison of charge injection with and without anodic bias at various potentials.

Main Results:

• A nine-fold increase in current intensity and charge injection capacity was observed.
• Optimal performance was achieved with a 0.7 V anodic bias.
• The applied bias remained within electrochemically safe limits.

Conclusions:

• The developed embedded neurostimulator effectively enhances neural stimulation parameters.
• Digital control of anodic bias offers a practical solution for improving neurostimulator performance.
• This technology holds promise for more effective neural tissue interfaces.