Unlike conventional systems that maintain stationary poles during frequency sweeps, a ‘pole-moving sweeping’ readout system dynamically adjusts the pole position, thus reducing errors caused by noise and variations in distance and angle. The platform employs an integrated folded structure combining mechanics and electromagnetics to achieve softness, biodegradability, and electromagnetic functionality. The system’s reader consists of an inductor, a programmable variable capacitor, and a resistor, while the sensor is a soft, biodegradable inductor–capacitor circuit. This design enables the creation of sensors with large inductance and small resistance, essential for long-distance wireless communication. The experimental validation involved a copper-coil reader and sensor, using an impedance analyser to measure phase at various distances and angles (with readout distance up to 30 cm and an angle tolerance up to 45° at 25 cm). The biodegradable sensors — made from magnesium-based conductors with different dielectrics for sensing modalities and embedded in a polylactic acid-based structure encapsulated in soft biodegradable elastomers — ensured softness and conformability, mechanical protection, biocompatibility, and controlled degradation over days to weeks and exhibited robust performance: the platform achieved long-distance readout up to 16 cm and angle tolerance up to 60° at 11 cm, substantially surpassing standard readout systems. The authors demonstrated the platform’s versatility through ex vivo strain sensing and in vivo pressure and temperature monitoring in the abdominal cavities of horses.
By mitigating measurement errors arising from noise and positional variability, this system is particularly well-suited to clinical environments where precise control of distance and angle is often infeasible. Its stability, biodegradability and long-range performance position it as a promising complement to traditional medical imaging techniques, especially in settings where surgery is already required and continuous, localized physiological monitoring could guide treatment. Future developments may incorporate additional sensing modalities, expanding the platform’s potential to capture a broader spectrum of physiological and chemical indicators and further advancing its clinical integration.
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