A cross-modal epidermal sensor enables single-channel fusion of biopotential and biomechanical signals

Disease monitoring typically requires the acquisition of multiple physiological signals with different modalities. Existing epidermal electronics use separate sensors for each modality, which necessitates a large footprint, high bandwidth and power consumption. We report a wearable electronic system that can fuse physiological signals with multiple modalities into a singlecross-modal biosignal (X-Sig). Leveraging hierarchical device architecture and in-sensor signal fusion strategy, X-Sigsensor concurrently acquires biopotential signals (e.g., electrocardiography and electromyography) and biomechanical signals (e.g., force myography and radial pulse) through a single channel. The single-channel X-Sig sensor is capable of continuous monitoring of multiple dynamic haemodynamics, including heart rate, pulse arrival time, diastolic and systolic blood pressure with high accuracy. In machine-learning-based gesture recognition, the X-Sig sensor reduced the decoding error rate by 7.8-fold compared to conventional electromyography. By fusing complementary modalities at the sensor level, X-Sig sensor provides a versatile platform for designing bandwidth-efficient and low-power wearable electronics.