Advancements in Glucose Monitoring: From Traditional Methods to Wearable Sensors

Accurate in vivo glucose monitoring is essential for effective diabetes management and for the care of pre-term infants in critical care. Glucose-monitoring techniques are broadly categorized into three types: invasive, minimally invasive, and non-invasive. Each method presents distinct advantages and challenges. Non-invasive glucose sensors, despite impressive advancements in recent years, still face issues with signal interference and accuracy, limiting their widespread clinical application. In contrast, implanted devices offer more reliable and consistent results in clinical settings, making them the current gold standard. This review provides an overview of the leading glucose-sensing technologies, detailing both their advantages and drawbacks. We discuss invasive techniques, such as implanted electrodes, which allow continuous glucose monitoring with high accuracy, but often come with risks of infection and discomfort. Minimally invasive methods, such as fluorescence sensors, Raman sensors, and microneedle arrays, aim to reduce discomfort while providing more precise measurements than non-invasive devices. Additionally, non-invasive methods, such as optical, infrared, and microwave techniques, are explored for their potential to provide pain-free, continuous glucose monitoring. Finally, the review highlights a brief comparison among the current technologies and future directions in the field, particularly the use of signal enhancement algorithms and integration with wearable devices.