Analytical Model for Blood Glucose Detection Using Electrical Impedance Spectroscopy

Abstract

Pathogens and adulterants in human feeding consumables can be readily identified according to their electrical properties. Electrical bioimpedance analysis (BIA) has been widely used for body contents characterization, such as blood, urine, lactate, and sweat. If the concentration of glucose in blood alters the electrical properties of the blood medium, then the impedance spectrum obtained by BIA can be used to measure glycemia. For some applications, artificial neural networks allow the correlation of these parameters both impedance and concentration of glucose by means of symbolic and statistical rules. According to our literature review, there is not any physical model that allows the interpretation of the relationship between blood’s electrical properties from impedance spectra and the concentration of glucose in blood plasma. This article proposes a simplified physical model for blood electrical conductivity as a function of concentration of glucose, based on Bruggeman’s effective medium theory. The equations of this model were obtained considering an insulating phase distribution diffused in a conductive matrix, in which red blood cells are represented by macroscopic insulating nuclei and glucose molecules by microscopic insulating particles. The impedance spectrum for different glucose concentrations (4.0 to 6.8 mmol/L) in a blood sample, published by Kamat Bagul (2014), were compared to the proposed model. The results showed a significant correlation with the experimental data, showing a maximum error of 5.2%. The proposed model might be useful in the design of noninvasive blood glucose monitoring systems.

A Survey on Current-Mode Interfaces for Bio Signals and Sensors

“…In a resistive or capacitive biosensor, the variations of the biological parameter to be measured are converted into impedance variations, in particular resistance or capacitance variations, respectively. An example of a resistive biosensor is represented by blood, whose electrical impedance varies depending on its glucose level [ 82 ], while capacitive biosensors have been successfully applied to the detection of proteins, nucleotides, heavy metals, saccharides, small organic molecules, and microbial cells [ 83 ]. To maintain circuit simplicity and, hence, the ease of on-chip integration, the traditional voltage approach for the conditioning of such types of sensors consists of inserting them into a simple voltage divider or a Wheatstone bridge that modifies its behavior depending on the measured values, as in Figure 7 and Figure 8 .…”

Recent advancements in noninvasive glucose monitoring and closed-loop management systems for diabetes

“…80 The mechanism of MHC is that glucose levels can be reflected through physiological indicators generated by basal metabolism. 81 Electrical technologies are based on the changes in the dielectric properties of glucose caused by different electrical signals, mainly including reverse iontophoresis (RI), [82][83][84][85][86] microwave, 48,[87][88][89][90][91][92][93] impedance spectroscopy, [94][95][96][97][98][99] electromagnetic sensing, [100][101][102][103] etc.…”

“…Studies have shown that maintaining a balance of electrolytes in the body is essential for health, and electrical impedance measurements can reflect changes in the electrolytes between the intracellular and extracellular fluids in the dermis due to changes in blood sugar levels. 94,95 In the complex skin structure, the dielectric properties of deep skin better reflect the changes in blood glucose levels, and the skin impedance measured at a high frequency AC range better reflects the dielectric properties of deep skin (Fig. 6C).…”

“…Electrical technologies are based on the changes in the dielectric properties of glucose caused by different electrical signals, mainly including reverse iontophoresis (RI), 82–86 microwave, 48,87–93 impedance spectroscopy, 94–99 electromagnetic sensing, 100–103 etc.…”

Evaluation of a Continuous Blood Glucose Monitor: A Novel and Non-Invasive Wearable Using Bioimpedance Technology

“…The rationale for use of bioimpedance to estimate BGL is based on this hypothesis and the identified experimental correlation between the two under controlled conditions. [18][19][20] The current study used a prototype NI-CGM in the form of a wearable ring that used bioimpedance technology. The prototype NI-CGM was used in an observational clinical study to collect bioimpedance data from a cohort of people with diabetes with the aim of developing a mathematical model to estimate BGL.…”