Hydrogel-based photonic sensor for a biopotential wearable recording system

Area of Science:

• Biomedical Engineering
• Materials Science
• Sensor Technology

Background:

• Wearable devices offer continuous physiological monitoring for applications like ambient-assisted living (AAL).
• Existing electroencephalogram (EEG) acquisition methods using conventional caps are uncomfortable and difficult to wear.
• Developing new, unobtrusive wearable solutions for EEG signal acquisition is a significant challenge.

Purpose of the Study:

• To present a novel optical fiber biosensor utilizing an electro-active polyacrylamide (PAAM) hydrogel.
• To enable contactless electrode technology for improved wearable EEG monitoring.
• To evaluate the electro-active properties and frequency response of the PAAM hydrogel for biopotential recording.

Main Methods:

• Development of an optical fiber biosensor based on a PAAM hydrogel.
• Experimental evaluation of the hydrogel's electro-active properties using an electric and optical setup.
• Application of a sinusoidal electric field to the hydrogel while passing light through it, with detection of modulated light.

Main Results:

• The PAAM hydrogel demonstrated adequate sensitivity in the microvolt (μV) range.
• The sensor exhibited a good frequency response suitable for biopotential recording.
• The contactless electrode principle was validated through experimental testing.

Conclusions:

• The developed PAAM hydrogel optical fiber biosensor is a promising candidate for wearable biopotential recording.
• This technology offers a more comfortable and unobtrusive alternative to conventional EEG caps.
• The sensor's performance supports its potential application in areas such as ambient-assisted living and brain-computer interfaces.