A wireless battery-less and moisture-resistant packaged glucose sensing system employing hydrogel-based inductive sensing technique and low-power ASIC for long-term glucose monitoring

A wireless and battery-less glucose sensing system has been demonstrated for future long-term implantable glucose monitoring. The proposed glucose sensing system employs an oscillator-based inductive sensor that detects a volumetric change of a glucose-sensitive hydrogel. A robust 3D-printed moisture-resistant package is used to encapsulate the sensing system for in-vitro characterization. An application-specific integrated circuit (ASIC) is designed to enable in-situ temperature characterization as well as system miniaturization. The overall system dissipates 600 mu W and exhibits a dimension of 6 mm x 6 mm x 25 mm. A rotation-insensitive wireless powering scheme has been demonstrated to reliably deliver power to a tube-shaped implantable system. The prototype sensor operated at 190 MHz can be wirelessly powered by a 6.78 MHz RF power source over a distance of 2 cm. The sensor achieves a glucose sensing resolution of 0.025-0.055 mM within a typical physiological glucose concentration between 4 mM and 10 mM at a typical human body temperature of 37 oC. The prototype sensor has demonstrated a reliable in-vitro operation for 60 days without noticeable performance degradation.

Automated summary

A wireless and battery-less glucose sensing system has been demonstrated for long-term implantable glucose monitoring. The system uses an oscillator-based inductive sensor and a glucose-sensitive hydrogel to detect glucose concentration. It has low power consumption and small size, and can operate reliably through wireless power delivery.