Remote detection of gastroesophageal reflux using an impedance and pH sensing transponder

In this work, we developed a dual-sensor system to monitor the symptoms in gastroesophageal reflux disease (GERD). The system consists of an implantable transponder and an external reader. The passive telemetry for signal transduction is based on an inductive link between two coil antennas. The reader supplies radio frequency power, obtains and stores the backscattered sensory data. The dual-sensor transponder detects both impedance and pH changes associated with the gastroesophageal reflux episodes and sends load-modulated signals back. Bench-top experiments were conducted to examine the robustness of the wireless transponding system. Preliminary in vivo experiments were conducted with a live pig. Our dual-sensor transponder system has successfully demonstrated its capability for effective GERD symptom monitoring.