Design of a high sensitive non-faradaic impedimetric sensor

Abstract

(B) Randles equivalent circuit for electrode electrolyte interface. Cdl is the charge capacitance due to double layer at interface; Rct is the charge transfer resistance due to redox reactions at interface; Rs is the solution resistance due to ion concentration and cell geometry; Zw is the Warburg impedance due to diffusion from bulk solution to interface. C) Graph showing the correlation between the real and imaginary parts of the impedance. Peak values are concentration (of the analyte under test) dependent. /Abstract-an electrochemical approach towards identifying antigen -antibody binding interactions is studied by using a non-faradaic impedimetric sensor fabricated on a printed circuit board (PCB) chip. An electrical methodology for detecting protein interactions at ultra-low concentrations (in the femtogram/mL) regime has been demonstrated. Nanoporous alumina with pore diameter of 200nm and pore depth of 250 nm was used as the signal amplifying medium. Cardiac biomarker, brain natriuretic peptide (BNP) was used as the study marker in characterizing the sensor's sensitivity. A sensitivity of 10 femtogram/mL was determined based on the impedimetric signal response. Sensitivity was determined through Nyquist plot analysis for the non-faradaic interactions of the protein biomolecules. This paper is the first demonstration of clinically relevant limit of detection with the BNP biomarker.

A wearable biochemical sensor for monitoring alcohol consumption lifestyle through Ethyl glucuronide (EtG) detection in human sweat

“…The measured impedance was identified to be dominated by the C dl , which is the capacitive of the double layer formed at the sensing electrode-fluid interface. We identified this observation to be in alignment with previously published literature by our group and many other researchers 37 38 39 40 41 . The formation of an affinity immunoassay on a conducting material i.e.…”

Portable Nanoporous Electrical Biosensor for Ultrasensitive Detection of Troponin-T

“…By determining the time constants of measured signal, it can be used to determine electronic/ionic conduction at the electrode surfaces, diffusion profile of molecules, charge-transfer and changes at the EDL [26,27]. In our work, we have used EIS to characterize dynamic changes occurring within EDL due to binding of cTnT.…”

“…These resistive components can be obtained from Z real . The described electrical parameters can be obtained by fitting the measured impedance data to Randel's equivalent circuit [27]. In our work, impedance measurements were taken by applying 10 mV sinusoidal signal at zero DC bias over 50 to 1200 Hz frequency range.…”

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“…Normally, EIS is performed using redox probes in a three-electrode setup, often modeled using the schematic diagram known as a Randle’s circuit. 17 The proposed platform can be represented by a modified version of this equivalent circuit model, which can be seen in Figure 1d . The initial component, R AuNP , represents the overall resistance offered by the gold nanoparticles printed on the electrodes.…”