Improving the in vivo stability and sensor lifetime with new blend membranes on CGM sensors†

Abstract

Continuous glucose monitoring (CGM) is essential for managing diabetes, including closed-loop (artificial pancreas) technology. However, the current lifetime of commercial glucose sensors used in CGM based on the electrochemical method is limited to 3–15 days. The instability or failure of implanted electrochemical glucose sensors caused by tissue reactions, outer membrane degradation, calcification, and delamination can decrease in vivo sensor accuracy and lifetime. Durable outer membrane materials with good biocompatibility are crucial to improve the accuracy and durability of long-term implantable electrochemical glucose sensors in vivo and overcome these obstacles. This study used PDMS/HydroThane as the outer membrane of the glucose sensors to demonstrate long-term in vivo stability in non-diabetic dogs for 28 days. The good biocompatibility and stability of the outer membrane contributed to the extended sensor lifetime. Additionally, the study evaluated the effect of oxygen on the performance of glucose sensors coated with PDMS/HydroThane blending membranes containing different PDMS contents. The results showed that glucose sensors coated with blending membranes of PDMS/HydroThane with a weight ratio of 10 : 50 were essentially independent of environmental PO₂ while blending membranes of PDMS/HydroThane with a weight ratio of 5 : 50 coated glucose sensors were affected by oxygen fluctuation. This new membrane was developed to increase the in vivo lifetime of CGM sensors with quick response time and good in vivo stability and provide valuable insights into the design and development of new glucose sensors for long-term CGM applications.