Hydrophilic Micro- and Macroelectrodes with Antibiofouling Properties for Biomedical Applications

Area of Science:

• Biomaterials Engineering
• Neuroscience
• Nanotechnology

Background:

• Implantable neural electrodes are crucial for recording neural activity and stimulation.
• Biofouling and inflammatory responses significantly degrade neural electrode performance over time.
• Long-term applications necessitate flexible, conductive electrodes with antibiofouling properties.

Purpose of the Study:

• To covalently functionalize carbon nanotube (CNT) fiber and film surfaces with phosphorylcholine (PC) molecules.
• To evaluate the impact of PC functionalization on CNT electrode properties, including hydrophilicity, antifouling nature, and electrochemical performance.
• To develop improved materials for neural electrodes that resist biofouling and inflammation.

Main Methods:

• Covalent functionalization of CNT surfaces with PC molecules.
• Evaluation of surface hydrophilicity using static contact angle measurements.
• Assessment of protein absorption to determine antifouling properties.
• Characterization of electrochemical properties and impedance of functionalized CNT assemblies.

Main Results:

• Functionalized CNT films showed significantly increased hydrophilicity, with contact angles decreasing from 134.4° to 15.7° after one cycle.
• Protein absorption on PC-functionalized CNT films was substantially lower compared to non-functionalized films.
• Crucially, the electrochemical properties and impedance of the CNT assemblies were maintained after PC functionalization.

Conclusions:

• Covalently functionalized CNT assemblies with PC molecules offer enhanced hydrophilicity and protein-fouling resistance.
• These findings suggest promising applications for developing advanced, low-impedance neural electrodes.
• The developed materials have the potential to improve the longevity and efficacy of neural implants by mitigating inflammatory responses.