3D printing of highly conductive and strongly adhesive PEDOT:PSS hydrogel-based bioelectronic interface for accurate electromyography monitoring.

PSS hydrogel-based bioelectronic interfaces have gained significant attention in various fields including biomedical devices, wearable devices, and epidermal electronics. However, the development of high-performance bioelectronic interfaces that integrate excellent conductivity, strong adhesion, and advanced processing compatibility remains a challenge. Herein, we develop a high-performance bioelectronic interface by 3D printing of a novel poly(vinyl alcohol-formaldehyde) (PVAF)-PEDOT:PSS composite ink. Such a PEDOT:PSS-PVAF ink exhibits favorable rheological properties for direct-ink-writing 3D printing, enabling the fabrication of high-resolution patterns and three-dimensional structures with high aspect ratios. Hydrogel bioelectronic interface printed by such PEDOT:PSS-PVAF ink simultaneously achieves high conductivity (over 100 S m), strong adhesion (31.44 ± 7.07 kPa), as well as stable electrochemical performance (charge injection capacity of 13.72 mC cm and charge storage capacity of 18.80 mC cm). We further integrate PEDOT:PSS-PVAF hydrogel bioelectronic interface to fabricate adhesive skin electrodes for electromyography (EMG) signal recording. The resultant EMG skin electrodes demonstrate superior performance and stability compared to commercial products, maintaining high signal-to-noise ratio of > 10 dB under varying weights and repetitive motions. These advantageous performance of PEDOT:PSS-PVAF based hydrogel bioelectronic interfaces may be helpful for diverse bioelectronic applications like healthcare monitoring and epidermal bioelectronics.