Electrocatalytic glucose sensor for long-term in vivo use

Area of Science:

• Biomedical Engineering
• Electrochemical Sensors
• Diabetes Technology

Background:

• Diabetes mellitus requires continuous glucose monitoring for effective management.
• Existing continuous glucose monitoring (CGM) systems face challenges with long-term stability and biocompatibility.
• Closed-loop systems for insulin delivery necessitate reliable and accurate glucose sensing.

Purpose of the Study:

• To develop and evaluate a catheter-shaped electrocatalytic glucose sensor for in vivo applications.
• To assess the sensor's long-term performance and biocompatibility in a closed-loop diabetes therapy system.
• To determine the feasibility of using electrochemical impedance for glucose concentration measurement.

Main Methods:

• Development of a catheter-shaped electrocatalytic sensor with a membrane-covered platinum electrode.
• Electrochemical impedance measurements at two frequencies as a function of glucose concentration.
• In vivo implantation of the sensor in the vena cava of sheep for extended monitoring.
• Histological examination of the explanted catheter for biocompatibility assessment.

Main Results:

• The sensor successfully determined glucose concentration in vivo for over 130 days in sheep.
• Tolerable deviations from reference glucose measurements were observed, with a mean error of 2.5 mmol/l.
• Histological examination after 211 days of implantation revealed good biocompatibility of all sensor materials.

Conclusions:

• The developed catheter-shaped electrocatalytic glucose sensor is feasible for long-term in vivo monitoring in diabetes therapy.
• The sensor demonstrates good stability, accuracy, and biocompatibility for potential use in closed-loop insulin delivery systems.
• Electrochemical impedance offers a viable principle for continuous glucose measurement in a clinical setting.