A New Sensor for measuring blood sugar level require no needles. Measuring blood sugar levels is crucial for people with Type I and Type II diabetes. The current method we all use to measure the blood glucose level are invasive, requires finger pricks which can be painful and inconvenient especially if one requires a more frequent or continuous monitoring. A promising alternative is the use of a non-invasive sensor that detects changes in the dielectric properties of blood, which vary with glucose concentration. This article explains how a dual-mode resonant sensor can measure blood sugar levels without the need for invasive procedures.
How the sensor works
This special sensor is placed on the skin and uses microwave resonance to measure glucose
levels. The sensor consists of three key metal components, referred to as A, B,
and G. A and B are close to each other, while G is positioned farther away and acts as a
ground reference.
In differential mode, a signal is applied to A and B with a different phase (opposite signals),
the electric fringe field generated stays between the two conductors, creating a shallow
penetration. This mode only interacts with the top layer of the skin. The other mode is the
common Mode where a signal is applied with the same phase to A and B (common signal),
the electric fields extend between A, B, and G. Because G is farther away, the fields
penetrate deeper into the tissue, reaching the blood vessels.
By combining the shallow readings from the DM and the deeper readings from the CM, the
sensor can differentiate between the signals coming from the skin and those from the blood.
The change in the permittivity (the way the body’s tissues respond to the microwaves) due to
glucose concentration in the blood is detected as a shift in the sensor’s resonant frequency.
This change can then be used to estimate blood glucose levels.
The sensor’s geometry is carefully designed so that in DM, the fields are confined to the skin,
while in CM, the deeper penetration reaches the blood vessels, enabling a more accurate
reading of blood glucose. The figure below shows how the sensor interacts with two different
layers: the first layer (MUT1) represents the skin, while the second layer (MUT2) represents
the blood vessels..
Benefits of the sensor
The sensor while being non-invasive, will require no more use of painful needles. It also has
the potential to be integrated in smart watches and smart bands which can allow you to
continuously measure you blood glucose level, just like you do with your heart rate and
oxygen level.
Current Design Challenges
The current design shows promising results in initial tests using phantom materials, which
mimic human tissue. However, one challenge is that the sensor’s sensitivity currently allows
measurement of only about 780 micrometers beneath the skin, while the actual distance to
blood vessels can be greater depending on the individual. Further development and
optimization of the sensor are needed to increase its depth sensitivity, allowing it to reliably
detect blood glucose in a wider range of skin types and thicknesses.
Conclusion
The dual-mode resonant sensor presents a new and innovative method for non-invasive
blood glucose measurement, offering a potential solution to replace painful, needle-based
monitoring methods. By using two modes—one that scans the skin and one that reaches the
blood—the sensor can focus on glucose levels while filtering out interference from the skin.
Although the technology is still in development, it holds great promise for making diabetes
management easier, less painful, and more convenient in the future. It can also be integrated
in your smart watch