A Biocompatible and Biodegradable LC Temperature Sensor Based on Dual-Layer Inductors

This article presents an inductor–capacitor (LC) passive wireless sensor for temporary internal body temperature monitoring. The LC sensor adopts a dual-layer inductor structure to avoid wiring process between layers and at the same time to enhance the readout signal. Besides, all parts of the LC sensor are made of biocompatible and biodegradable materials, which can avoid a secondary surgical operation injury. The measured sensitivity of the sensor achieves 4.11 MHz/°C in the range of 36 °C–40 °C, and the resolution reaches 0.1 °C. To reduce the readout distance effect, the deembedding calibration method is applied to calibrate the designed LC temperature sensor. The degradation experiment shows that the main parts of the sensor have been degraded after 12 days of immersing in 37 °C phosphate-buffered saline (PBS). The tissue environment experiment indicates that the sensor signal can be clearly read after being embedded in biological tissue.