Thermoresponsive Soft and Self-Anchoring Cuff Electrode for Chronic Peripheral Interfaces

Abstract

Cuff type neural interfaces are widely used for peripheral nerve stimulation and monitoring. The traditional cuff electrodes typically require sutures or rigid fixation; this can lead to nerve damage and unstable electrode contact, ultimately compromising long-term performance. To address these issues, we developed a thermoresponsive soft and self-anchoring (TSSA) cuff electrode that automatically wraps around nerves in response to body temperature. This functionality is made possible by a shape memory polymer (SMP) substrate designed to soften and deform near physiological temperatures, enabling the electrode to self-close and securely hold without the need for an external force. Additionally, the SMP provides gentle yet stable contact with the nerve, thereby enhancing biocompatibility. In vivo experiments using rat sciatic nerves demonstrated reliable recordings of mechanically evoked nerve responses for 16 weeks, with signal-to-noise ratios reaching approximately 10 and stable impedance profiles. Histological and immunohistochemical analyses showed no significant tissue damage or inflammatory responses caused by the implanted device. By removing the need for sutures and providing a soft, stable contact with the nerve, the cuff electrode represents a safe and durable platform for chronic neural interfacing. The proposed technology holds strong potential for use in prosthetic limbs and bioelectronic medicine.