RF Remote Blood Glucose Sensor and a Microfluidic Vascular Phantom for Sensor Validation

Abstract

Diabetes has become a major health problem in society. Invasive glucometers, although precise, only provide discrete measurements at specific times and are unsuitable for long-term monitoring due to the injuries caused on skin and the prohibitive cost of disposables. Remote, continuous, self-monitoring of blood sugar levels allows for active and better management of diabetics. In this work, we present a radio frequency (RF) sensor based on a stepped impedance resonator for remote blood glucose monitoring. When placed on top of a human hand, this RF interdigital sensor allows detection of variation in blood sugar levels by monitoring the changes in the dielectric constant of the material underneath. The designed stepped impedance resonator operates at 3.528 GHz with a Q factor of 1455. A microfluidic device structure that imitates the blood veins in the human hand was fabricated in PDMS to validate that the sensor can measure changes in glucose concentrations. To test the RF sensor, glucose solutions with concentrations ranging from 0 to 240 mg/dL were injected into the fluidic channels and placed underneath the RF sensor. The shifts in the resonance frequencies of the RF sensor were measured using a network analyzer via its S11 parameters. Based on the change in resonance frequencies, the sensitivity of the biosensor was found to be 264.2 kHz/mg·dL−1 and its LOD was calculated to be 29.89 mg/dL.

Is Raman the best strategy towards the development of non-invasive continuous glucose monitoring devices for diabetes management?

“…However, due to the susceptibility to many endovascular variables, such as pharmacological treatment, internal erythrocyte aggregation, free fatty acid concentration and chylomicrons (ULDLs), this technology cannot be used to develop BGM devices without a complex algorithm, still lacking, to extract glucose information (Shokrekhodaei and Quinones, 2020). RadioFrequency Sensor Technology (RFST) is another approach to monitor the different levels of blood glucose concentration (Moore, 2009;Yilmaz et al, 2019;Yunos et al, 2021). Compared to sensors with different mechanisms, Alertgy ® (Alertgy Ltd., United States) and UBAND ™ (Know Labs, United States) RF devices are advantageous in terms of their fast response (Shang et al, 2022;Meet Alertgy NICGM, 2022. Blood Glucose Monitoring.…”

“…RadioFrequency Sensor Technology (RFST) is another approach to monitor the different levels of blood glucose concentration ( Moore, 2009 ; Yilmaz et al, 2019 ; Yunos et al, 2021 ). Compared to sensors with different mechanisms, Alertgy ® (Alertgy Ltd., United States) and UBAND™ (Know Labs, United States) RF devices are advantageous in terms of their fast response ( Shang et al, 2022 ; Meet Alertgy NICGM, 2022 .…”

On the Selectivity of Planar Microwave Glucose Sensors with Multicomponent Solutions

“…Some external parameters, such as the Signal-to-Noise Ratio or the frequency and amplitude resolutions, will be key for the finally achieved accuracy in each case. However, if ideal measurement conditions are considered and linearity is seen in the measurements, the Limit of Detection (LOD) of the sensors can be computed using the well-known 3σ/m rule [84], where σ is the standard deviation for the reference solution and m is the slope for the fitted model (Figures 5-7). It can be seen that in our case, the slope depends on the albumin concentration, and therefore different LOD are obtained for different sets of solutions, as it also occurred with the sensitivities.…”

A planar microwave sensor for noninvasive detection of glucose concentration using regression analysis

“…The designed sensor has a dimension of 68 × 48 × 1.6 mm 3 with a frequency shift of 650 MHz. Reference [17] has a stepped impedance resonator at 3.528 GHz. A microfluidic device structure has been fabricated in polydimethylsiloxane(PDMS) that can sense the changes in glucose concentrations.…”