In-vivo actuation of compliant dielectric elastomer artificial muscles via a peripheral nerve interface

Interfacing soft actuators with biological nervous systems remains a major challenge in flexible bioelectronics. Here, we present the first in-vivo neural control of compliant reinforced dielectric elastomer actuators (rDEAs) functioning as implanted artificial muscles. To establish the clinical benchmark for this platform , we targeted the reanimation of facial paralysis, a condition requiring soft, low-force actuation. Pre-clinical in-vitro testing on anatomically realistic human skull models demonstrates that rDEAs can reproduce smiling displacements, achieving 14% strain under physiologically relevant loads. To validate core bio-electronic viability, the encapsulated, fiber-reinforced rDEAs were implanted subcutaneously in an anesthetized rat model. The devices generated controlled and repeatable tissue displacements up to 0.78 mm at 7 kV, utilizing ultrasound gel to successfully overcome biological tissue damping. When interfaced with the sciatic nerve via flexible cuff electrodes, the actuators responded in real-time to efferent neural signals, enabling synchronized movement. Furthermore, because rDEAs operate as compliant capacitors, maintaining the electrostatically ’acti-vated’ state required for resting facial symmetry draws near-zero steady-state power. This first in-vivo demonstration establishes a robust bioelectronic platform for neuro-controlled artificial muscles, marking a critical step toward the dynamic reanimation of paralyzed tissues.