Dynamic Modulation of OECT-Based Inverters for In Situ Electrophysiological Monitoring

Area of Science:

• Materials Science
• Electronics
• Biomedical Engineering

Background:

• Organic electrochemical transistors (OECTs) offer low voltage operation and flexibility, making them suitable for biosensors and neuromorphic applications.
• Instability in OECTs, caused by microstructural changes and redox side reactions, hinders reliable performance in bioelectronic systems.

Purpose of the Study:

• To develop a dynamic modulating system for OECT-based inverters to enhance operational stability and voltage amplification.
• To demonstrate the system's capability in maintaining high-voltage gain and enabling stable, high-fidelity biosensing applications.

Main Methods:

• Real-time scanning of voltage transfer characteristics and adjustment of operating voltage to dynamically control OECT inverter conditions.
• Fabrication and integration of stretchable complementary circuits with the dynamic modulating system.
• In situ monitoring of electrooculogram (EOG) signals using the developed wearable biosensing system.

Main Results:

• The OECT inverter maintained a high voltage gain (>34.58 V/V) under dynamic system modulation, compared to a rapid deterioration to 3.11 V/V without modulation.
• Stretchable complementary circuits integrated with the system enabled high-fidelity EOG monitoring with a signal-to-noise ratio >32.59 dB for over 90 minutes.
• The system demonstrated a reliable wearable biosensing method for bioelectronics with inherently unstable devices.

Conclusions:

• A dynamic modulating system can significantly improve the operational stability and performance of OECT-based bioelectronics.
• This strategy provides a robust solution for wearable biosensing, overcoming the limitations of device instability.
• The developed approach offers a new pathway for creating reliable bioelectronic devices and systems.