Polysilicon based flexible temperature sensor for high spatial resolution brain temperature monitoring

Area of Science:

• Biomedical Engineering
• Materials Science
• Neuroscience

Background:

• Accurate brain temperature monitoring is crucial for understanding neurological conditions.
• Existing methods may lack the resolution or flexibility for detailed brain temperature mapping.
• Polysilicon thermistors offer potential for miniaturized, high-performance temperature sensing.

Purpose of the Study:

• To develop and characterize a flexible temperature sensor for high-resolution brain temperature monitoring.
• To evaluate the sensor's performance in vitro and in vivo, including its correlation with electrocorticography (ECoG) signals.

Main Methods:

• Fabrication of a flexible temperature sensor utilizing ultra-small polysilicon thermistors.
• In vitro testing for sensitivity, resolution, thermal hysteresis, and long-term stability.
• In vivo experiments to correlate localized brain temperature with ECoG signals during spreading depolarization.

Main Results:

• Achieved a temperature coefficient of resistance (TCR) of -0.0031/°C and a resolution of 0.1°C.
• Demonstrated low thermal hysteresis (<0.1°C) and minimal drift (<0.3°C over 3 days) with a silicon nitride passivation layer.
• Observed a clear correlation between localized brain temperature and ECoG signals during in vivo tests.

Conclusions:

• The developed flexible temperature sensor is suitable for high-resolution brain temperature mapping.
• Its small size and flexibility enable multimodal monitoring in space-constrained applications.
• This technology can advance the study of brain temperature dynamics and neurological events.