Koirala Gyan Raj, Kim Eun-Seong, Dhakal Rajendra, Chuluunbaatar Zorigt, Jo Yong Hwa, Kim Sung-Soo, Kim Nam-Young
RFIC Fusion Laboratory, Department of Electronic Engineering, Kwangwoon University Seoul South Korea
Department of Computer Science and Engineering, Sejong University Seoul South Korea.
RSC Adv. 2018 Sep 24;8(58):33072-33079. doi: 10.1039/c8ra04243h.
Passive sensors provide a new route for the characterization of concentration-dependent radiofrequency parameters with high reproducibility in real time. We propose a microfabricated resonator realized using integrated passive device technology for the sensitive detection and characterization of glucose. Experimental results verify the high performance of the proposed biosensor, because radiofrequency parameters such as resonance frequency (from 0.541 to 1.05 GHz) and reflection coefficient (from -34.04 to -24.11 dB) linearly vary in response to deionized water and subsequent iterative measurements of different glucose concentrations (from 50 to 250 mg dL). The biosensor has a very low limit of detection of 8.46 mg dL, a limit of quantitation of 25.63 mg dL, a minimum frequency sensitivity of 29 MHz, and a minimum magnitude sensitivity of 0.22 dB. Moreover, the coupling coefficient consistently decreases with the increasing glucose concentration. We also used the measured radiofrequency parameters to determine the unknown permittivity of glucose samples through mathematical modeling. A decreasing trend in the loss tangent and an increasing trend in the characteristic wave impedance were observed with the increase of glucose concentration. The reproducibility of the sensor was verified through iterative measurements on the same sensor surface and subsequent study of surface morphology.
无源传感器为实时高重现性地表征浓度依赖性射频参数提供了一条新途径。我们提出了一种采用集成无源器件技术实现的微纳制造谐振器，用于葡萄糖的灵敏检测和表征。实验结果验证了所提出的生物传感器的高性能，因为诸如谐振频率（从0.541到1.05 GHz）和反射系数（从-34.04到-24.11 dB）等射频参数会随着去离子水以及随后不同葡萄糖浓度（从50到250 mg/dL）的迭代测量而线性变化。该生物传感器具有非常低的检测限，为8.46 mg/dL，定量限为25.63 mg/dL，最小频率灵敏度为29 MHz，最小幅度灵敏度为0.22 dB。此外，耦合系数随着葡萄糖浓度的增加而持续降低。我们还通过数学建模利用测量得到的射频参数来确定葡萄糖样品的未知介电常数。随着葡萄糖浓度的增加，观察到损耗角正切呈下降趋势，特征波阻抗呈上升趋势。通过在同一传感器表面进行迭代测量并随后研究表面形态，验证了该传感器的重现性。
