On the Selectivity of Planar Microwave Glucose Sensors with Multicomponent Solutions

Abstract

The development of glucose concentration sensors by means of microwave planar resonant technology is an active field attracting considerable attention from the scientific community. Although showing promising results, the current experimental sensors are facing some fundamental challenges. Among them, the most critical one seems to be the selectivity of glucose concentration against the variations of the concentrations of other components or parameters. In this article, we investigate the selectivity of microwave planar resonant sensors when measuring multicomponent solutions. Three sensors are involved, two of them having been designed looking for a more simplified system with a reduced size, and the third one has been specially developed to improve the sensitivity. The performance of these sensors is thoroughly assessed with a large set of measurements involving multicomponent solutions composed of pure water, NaCl, albumin at different concentrations and glucose at different concentrations. The impact of the simultaneous variations of the concentrations of glucose and albumin on the final measurements is analyzed, and the effective selectivity of the sensors is discussed. The results show a clear influence of the albumin concentration on the measurements of the glucose concentration, thereby pointing to a lack of selectivity for all sensors. This influence has been modeled, and strategies to manage this selectivity challenge are inferred.

Microwave Humidity Sensor for Early Detection of Sweat and Urine Leakage

“…We should mention that, despite the fact that the proposed sensor detects the presence of liquid in fabric, it cannot be considered a microwave liquid sensor. Liquid sensors are mainly focused on the characterization of the complex dielectric constant of a certain liquid under study [4][5][6][7] or on the determination of the composition of liquid mixtures [51,57,[71][72][73][74][75][76][77][78][79][80][81]. Such sensors are typically implemented by means of fluidic channels [51,57,[71][72][73][74][75][76][77].…”

A new rectangular dielectric resonator sensor for glucose measurement: Design, modeling, and experimental validation

“…21,22 Because of the resonators' high-frequency response, certain variations in the permittivity of the nearby dielectric material (which includes blood) will be represented in the resonant amplitude and frequency of the resonating response. There are reports of non-invasive glucose sensors using spiral resonators of myriad shapes, split-ring resonators, [23][24][25][26][27] resonators based on defected ground structures and microstrip patch antennas, [28][29][30][31][32][33] and dielectric resonators. 1,34,35 Such resonators can be employed for a variety of applications, including ethanol gas detection, 36 contactless detection of Escherichia coli bacterium concentration, 37 complex permittivity measurement, 38 and solvent characterization with potential uses for chemical compounds.…”

Estudio de selectividad frente a disoluciones multicomponente de sensores de glucosa mediante tecnología planar de microondas

“…Tras más de una década de desarrollo de estos sensores, en este trabajo analizamos el reto de la selectividad de los actuales sensores de glucosa basados en resonadores de microondas (Juan et al, 2023). Con ese fin, dentro de los sensores basados en Qu, consideraremos un estudio comparativo que incluye el problema de simplificación y reducción de tamaño, así como el de mejora de la sensibilidad.…”

“…Figura 2: Respuestas de los sensores midiendo una muestra de agua pura. Adaptado deJuan et al (2023).…”