Radio frequency based label-free detection of glucose

We investigated the frequency based mediator-free glucose sensor in the radio-frequency (RF) range. Frequency dependent power signal showed clear dependence on the glucose concentration with free enzymatic condition. Also, the passive electrical components such as the resistance, inductance, shunt conductance, and capacitance were extracted based on the transmission line model for further analysis. These various parameters proposed by the signal processing provided more effective verification for instant multi-components in-situ readings without any added supporters. Additionally the residual signal (RS), impedance (Z), and propagation constant (gamma) were also calculated from measured S-parameters for glucose analysis. These parameters basically showed amplitude variation and interestingly, some parameters such as inductance and impedance showed frequency shift of resonance dip. The results support that the frequency based sensing technique including the parameter based analysis can enable effective multi-dimensional detection of glucose. Moreover, this technique showed that glucose sensing is also possible over a diabetic patient's serum. (C) 2013 Elsevier B.V. All rights reserved.