Continuous Glucose Monitoring: Long-Term Implantable Sensor Approach

Problems with existing glucose monitoring technology have resulted in poor compliance with recommended monitoring guidelines by patients with diabetes. To achieve the goal of tight glucose control by patients with diabetes, a long-term implantable glucose sensor should meet the following functional requirements: it should be a one-time minimally invasive implantable with a wireless external unit; provide on-demand real-time glucose levels and trends; operate for up to 12 months after implantation with infrequent recalibration; contain built-in hypoglycemic and hyperglycemic alarms; and have an ergonomically designed, external, wearable user interface. Measurements of glucose in interstitial fluid (ISF) can be used for long-term monitoring. A novel approach to continuous and long-term glucose sensing could be based on measuring the changes in fluorescence of glucose-sensitive indicator molecules. To measure these changes in fluorescence a miniature optoelectronic device with a glucose sensitive indicator could be implanted subcutaneously for long-term remote operation. The fluorescence-based glucose sensing process is reversible and does not consume glucose. The combination of fluorescence-based glucose detection, sensor miniaturization and the use of biomaterials, inducing neovascularization at the implant site, opens the opportunity for achieving the requirements for long-term, continuous and convenient glucose monitoring.