Fabric-substrated capacitive biopotential sensors enhanced by dielectric nanoparticles

Wearable biopotential sensing devices are essential to long-term and real-time monitoring of human health. Non-contact, capacitive sensing electrodes prevent potential skin irritations, and are thus beneficial for long-term monitoring. Existing capacitive electrodes are either connected to a separate control circuit via external wires or have limited sensing capacitances, which leads to low signal qualities. This study demonstrates a stretchable capacitive sensing device with integrated electrodes and control electronics, with enhanced signal qualities. The electrodes and the control electronics are fabricated on a common fabric substrate for breathability and strain-limiting protection. The stretchable electrodes are based on an island-bridge design with a stretchability as high as ∼ 100%, and an area ratio as high as ∼ 80%. By using a dielectric calcium copper titanate (CCTO) composite as the adhesive layer, the electrode capacitance can be increased, yielding an enhanced signal-to-noise ratio (SNR) in the acquired biopotentials. This device offers a convenient and comfortable approach for long-term non-contact monitoring of biopotential signals.