Soft biodegradable implants for long-distance and wide-angle sensing.

Abstract

Monitoring internal physiological signals is essential for effective medical care¹, yet most current technologies rely on external measurements or imaging systems that cannot capture enough deep-tissue dynamics^2-6. Implantable devices offer a solution, but conventional designs often require batteries or magnets^7-11, which carry risks during removal, and existing biodegradable sensors based on passive inductor-capacitor circuits are limited by short readout distances and unstable communication issues^12-19. Here we describe a soft, biodegradable, wireless sensing device that can monitor pressure, temperature and strain over long distances (up to 16 cm), maintaining accuracy across varying positions and angles. This is achieved through a 'pole-moving sweeping' readout system combined with a folded structure that integrates mechanical flexibility with electromagnetic function. In vivo tests in the abdominal cavity of horses reliably captured deep-tissue pressure and temperature, and ex vivo measurements demonstrated accurate strain monitoring without strict positional control. The long-distance and wide-angle readout of soft biodegradable implants holds translational promise for accessing deep-tissue physiological signals.