A reusable robust radio frequency biosensor using microwave resonator by integrated passive device technology for quantitative detection of glucose level

Abstract

A reusable robust radio frequency (RF) biosensor with a rectangular meandered line (RML) resonator on a gallium arsenide substrate by integrated passive device (IPD) technology was designed, fabricated and tested to enable the real-time identification of the glucose level in human serum. The air-bridge structure fabricated by an IPD technology was applied to the RML resonator to improve its sensitivity by increasing the magnitude of the return loss (S21). The resonance behaviour, based on S21 characteristics of the biosensor, was analysed at 9.20 GHz with human serum containing different glucose concentration ranging from 148-268 mg dl(-1), 105-225 mg dl(-1) and at a deionised (D) water glucose concentration in the range of 25- 500 mg dl(-1) for seven different samples. A calibration analysis was performed for the human serum from two different subjects and for D-glucose at a response time of 60 s; the reproducibility, the minimum shift in resonance frequency and the long-term stability of the signal were investigated. The feature characteristics based on the resonance concept after the use of serum as an analyte are modelled as an inductor, capacitor and resistor. The findings support the development of resonance-based sensing with an excellent sensitivity of 1.08 MHz per 1 mg dl(-1), a detection limit of 8.01 mg dl(-1), and a limit of quantisation of 24.30 mg dl(-1).

Capacitive Biosensors and Molecularly Imprinted Electrodes

“…When an analyte is injected into the RF biosensor, changes will occur owing to the inductive and capacitive effects [38]. These changes will cause losses and considerable shifts in the resonance frequency of the device.…”

“…The change in capacitance is proportional to the dielectric constant and the distance between the biomolecule layer and the dielectric layer. A reusable robust RF biosensor was developed by Kim et al [38] to monitor real-time glucose level in human serum. The resonance behaviour of the system was analysed with human serum samples containing different glucose concentrations ranging from 148–268 mg·dL −1 , 105–225 mg·dL −1 and at a deionized water glucose concentration in the range of 25–500 mg·dL −1 .…”

Coplanar Waveguide Microwave Sensor for Label-Free Real-Time Glucose Detection

“…Microwave sensing technique utilizes the glucose concentration dependent dielectric constant for glucose level measurements. In literature, various microwave glucose sensor designs have been reported, such as intertwined spiral inductor coupled with an interdigital capacitor structure [11], air bridge structure on rectangular meandered line [12] fabricated on GaAs and theoretical modeling of artificial transmission line section implemented in microstrip technology [13] etc. Li [14] reported Distributed MEMS Transmission Line (DMTL) glucose biosensor on silicon.…”

Microfluidic Biosensor Based on Microwave Substrate-Integrated Waveguide Cavity Resonator

“…For instance, in [14], even 50 cells of HepaG2 (a human cancer cell) could be detected with an RF biosensor (size 2.4 mm × 2.4 mm) using a planar LC resonant circuit. In [15], an MEMS-based glucose biosensor using a rectangular meandered-line resonator was proposed, with a size of only 2 mm × 1.8 mm. Nevertheless, micro-nano-sized RF biosensors require a more complex and detailed measurement system, for instance, RF probe station [9].…”