The conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) is increasingly used for implantable electrodes. This review discusses the key aspects of PEDOT-based implantable electrodes for neural recording, stimulation and electromyography.

Future electronics call for materials with mechanical toughness, flexibility, and stretchability. Moreover, self-healing and recyclability are highly desirable to mitigate the escalating environmental threat of electronic waste (e-waste). Herein, we report a stretchable, self-healing, and recyclable material based on a mixture of the conductive polymer poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) with a custom-designed polyurethane (PU) and polyethylene glycol (PEG). This material showed excellent elongation at brake (∼350%), high toughness (∼24.6 MJ m⁻³), moderate electrical conductivity (∼10 S cm⁻¹), and outstanding mechanical and electrical healing efficiencies. In addition, it demonstrated exceptional recyclability with no significant loss in the mechanical and electrical properties after being recycled 20 times. Based on these properties, as a proof of principle for sustainable electronic devices, we demonstrated that electrocardiogram (ECG) electrodes and pressure sensors based on this material could be recycled without significant performance loss. The development of multifunctional electronic materials that are self-healing and fully recyclable is a promising step toward sustainable electronics, offering a potential solution to the e-waste challenge.

Self-healable, conductive, soft, and stretchable electronic materials have become research hotspots in wearable and bioelectronic devices for healthcare monitoring. In this study, conductive, soft, stretchable, self-healing, highly adhesive, and biocompatible conductive polymer films were obtained by mixing poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS), ethylene glycol (EG), and tannic acid (TA). The films with optimized composition demonstrated very attractive properties for wearable electronics and bioelectronics, including a conductivity of ∼17 S cm⁻¹, a low Young's modulus of ∼450 kPa, stretchability of ∼90% strain, outstanding electrical stability during stretching (2% resistance change at 30% strain), and strong adhesion on several substrates. Notably, the films exhibited outstanding autonomous and cut-stick healing properties, enabled by the addition of TA. Furthermore, the films exhibited no signs of cytotoxicity, making them suitable for biomedical applications. Epidermal electrodes prepared using these materials exhibit low skin-electrode impedance at low frequencies (1–100 Hz) and high quality for electrocardiography (ECG) and electromyography (EMG) signal recordings. This study promotes the development of innovative wearable biomedical devices and contribute to personalized healthcare monitoring.

Printable, self-healing, stretchable, and conductive materials have tremendous potential for the fabrication of advanced electronic devices. Poly(3,4-ethylenedioxithiopene) doped with polystyrene sulfonate (PEDOT:PSS) has been the focus of extensive research due to its tunable electrical and mechanical properties. Owing to its solution-processability and self-healing ability, PEDOT:PSS is an excellent candidate for developing printable inks. In this study, we developed printable, stretchable, dry, lightly adhesive, and self-healing materials for biomedical applications. Polyurethane diol (PUD), polyethylene glycol, and sorbitol were investigated as additives for PEDOT:PSS. In this study, we identified an optimal printable mixture obtained by adding PUD to PEDOT:PSS, which improved both the mechanical and electrical properties. PUD/PEDOT:PSS free-standing films with optimized composition showed a conductivity of approximately 30 S cm⁻¹, stretchability of 30%, and Young’s modulus of 15 MPa. A low resistance change (<20%) was achieved when the strain was increased to 30%. Excellent electrical stability under cyclic mechanical strain, biocompatibility, and 100% electrical self-healing were also observed. The potential biomedical applications of this mixture were demonstrated by fabricating a printed epidermal electrode on a stretchable silicone substrate. The PUD/PEDOT:PSS electrodes displayed a skin-electrode impedance similar to commercially available ones, and successfully captured physiological signals. This study contributes to the development of improved customization and enhanced mechanical durability of soft electronic materials.

Highly stretchable and flexible bioelectronics should form close contact with skin and tissues while being able to withstand the stresses and strains endured by the body in order to reliably monitor physiological signals over time. Here, we report highly stretchable poly 3,4-ethylenedioxythiophene: polystyrene sulfonate (PEDOT:PSS) films printed on thermoplastic polyurethane (TPU) substrates. We established the stabilityof the device conductivity under high strains up to 600%. The printed PEDOT:PSS film enabled the fabrication of printed organic electrochemical transistors with an ON/OFF ratio of ∼450 on a flexible substrate. We also acquired physiological signals from measuring the skin conductance arising from changes in sweat volume by directly interfacing a printed PEDOT:PSS-based sensor on TPU with human skin. Stretchable printed PEDOT:PSS films on TPU provide a facile method of producing highly stable stretchable sensors for bioelectronic applications, enabled with simple and direct printing fabrication.