Biodegradable barometric endoradiosonde for biotelemetry applications

In the present work, the design, the testing and the implementations of a biodegradable and biocompatible capacitive barometric endoradiosonde to be swallowed or implanted in the human body is reported. The biodegradable requirement has been achieved exploiting Polycaprolactone (biodegradable polymer - PCL) and the technique of printing thin gold films on it (200-400 nm thick). The overall system is a hysteresis comparator whose oscillation frequency depend on a pressure sensitive capacitor. The final implementation fully satisfies the requirements of small size (9.5 x 4.5mm), biocompatibility and biodegradability (PCL used as substrate), high speed (steady fosc=4.89 MHz), high frequency sensitivity (-0.548 MHz/kPa).