Researchers have developed a non-invasive microwave-based biosensor that can accurately monitor blood glucose levels without the need for finger-prick tests, marking a notable step forward in diabetes care.
Study: Blood Glucose Monitoring Biosensor Based on Multiband Split-Ring Resonator Monopole Antenna. Image Credit: everydayplus/Shutterstock.com
A recent article in Biosensors explores this innovation in detail, highlighting the growing importance of painless, real-time glucose monitoring tools as diabetes rates rise worldwide.
Traditional invasive methods often cause discomfort, making the case for advanced technologies that eliminate the need for blood samples while still delivering precise results. This study stresses that for such devices to be truly viable, they must also meet rigorous safety standards to ensure user comfort and regulatory approval.
Background
Diabetes management often hinges on continuous monitoring of blood glucose levels, typically through finger-prick tests or continuous glucose monitors (CGMs). These approaches, although widely used, can lead to discomfort or anxiety over time. As a result, non-invasive monitoring technologies are gaining traction. These systems use methods such as optical, ultrasonic, and microwave sensing to estimate glucose levels through the skin—minimizing discomfort while aiming to deliver the same level of accuracy and specificity.
An important consideration in the development of these devices is the specific absorption rate (SAR), which measures how much electromagnetic energy is absorbed by body tissue. Regulatory agencies like the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the Federal Communications Commission (FCC) set firm SAR limits to ensure devices are safe for prolonged human use. Staying within these limits is essential for biosensors to be considered for clinical deployment.
The Current Study
This study focused on designing and validating a non-invasive biosensor built around a microwave sensor capable of detecting subtle changes in glucose concentration using multiple resonances. To ensure stability and repeatability in readings, the researchers developed a customized housing unit to secure the user’s fingertip during each measurement.
The sensor was tested on four individuals—two healthy and two diabetic—under carefully controlled conditions. Each participant fasted for six hours before the first reading and had a follow-up measurement two hours after eating. To reduce variability, participants washed their hands and remained seated and still during each test. The housing included a fixed-position guide and a pressure isolation layer to minimize fluctuations caused by pressure or fingertip positioning.
Readings from the biosensor were then compared to reference glucose values obtained from traditional methods. Researchers analyzed both the magnitude and phase of the reflection coefficient across multiple resonances, allowing for a robust evaluation of how the sensor responded to glucose level changes.
Results and Discussion
The sensor showed clear and consistent changes in frequency response as glucose levels varied. Data presented in Table 5 demonstrated distinct frequency shifts that corresponded with different glucose concentrations, particularly at higher levels, indicating the sensor’s potential for reliably detecting glucose variation.
The standard deviation in measurements across participants suggested that the biosensor offered a high level of reliability. Tests conducted both in fasting and post-meal states revealed predictable and consistent changes, reinforcing the sensor’s responsiveness to physiological glucose fluctuations.
Another key outcome was the confirmation that SAR levels remained well within ICNIRP and FCC guidelines. This is especially important for a device intended for regular or continuous use, as safety compliance is a major factor in patient acceptance and regulatory clearance.
Conclusion
This study highlights the successful development of a non-invasive biosensor for glucose monitoring, addressing many limitations of current invasive methods. The sensor demonstrated reliable accuracy and strong safety compliance, suggesting it could offer a practical and more comfortable solution for individuals managing diabetes.
Beyond its immediate application in glucose monitoring, this work sets the stage for broader advancements in non-invasive health tracking technologies. Future studies are encouraged to explore long-term performance, real-world usability, and adaptations of this platform for monitoring other vital biomarkers.
Journal Reference
Elsheakh D.N., Mohamed E-H, et al. (2025). Blood Glucose Monitoring Biosensor Based on Multiband Split-Ring Resonator Monopole Antenna. Biosensors 15(4):250. DOI: 10.3390/bios15040250, https://www.mdpi.com/2079-6374/15/4/250