DNA Hybridization Sensors Based on Electrochemical Impedance Spectroscopy as a Detection Tool

Abstract

Recent advances in label free DNA hybridization sensors employing electrochemical impedance spectroscopy (EIS) as a detection tool are reviewed. These sensors are based on the modulation of the blocking ability of an electrode modified with a probe DNA by an analyte, i.e., target DNA. The probe DNA is immobilized on a self-assembled monolayer, a conducting polymer film, or a layer of nanostructures on the electrode such that desired probe DNA would selectively hybridize with target DNA. The rate of charge transfer from the electrode thus modified to a redox indicator, e.g., [Fe(CN)6]3−/4−, which is measured by EIS in the form of charge transfer resistance (Rct), is modulated by whether or not, as well as how much, the intended target DNA is selectively hybridized. Efforts made to enhance the selectivity as well as the sensitivity of DNA sensors and to reduce the EIS measurement time are briefly described along with brief future perspectives in developing DNA sensors.

Use of nanomaterials for impedimetric DNA sensors: A review

“…In particular, EIS is becoming an attractive electrochemical tool for numerous applications either in 181 immuno- [51][52][53] or in genosensing field [16,54] In the first case the parameter of interest in the study is the capacitance of the double layer formed 210 between the solution and the electrode surface. No additional reagent is required for non-faradic 211 impedance spectroscopy.…”

“…Due to its ability of directly probing the interfacial properties of a modified electrode, the technique 179 is rapidly developing as a tool for studying biorecognition events at the electrode surface [23,[48][49][50]. 180In particular, EIS is becoming an attractive electrochemical tool for numerous applications either in 181 immuno- [51][52][53] or in genosensing field [16,54] In the first case the parameter of interest in the study is the capacitance of the double layer formed 210 between the solution and the electrode surface. No additional reagent is required for non-faradic 211 impedance spectroscopy.…”

Gene Specific Impedimetric Bacterial DNA Sensor for Rheumatic Heart Disease

“…1 inset). C dl is in series with R s and parallel to R ct [21]. The R ct of bare Au was lower than that of Au/MPA/PAMAM (not shown in the figure).…”

Quantum dot-based microfluidic biosensor for cancer detection

“…20 The modification over the chip surface causes a change in its R ct value and in case of a DNA biosensor, the change in R ct value may be induced by hybridization or the conformational changes of DNA to an electrical signal. 12 The modification of QCdSe-LB/ITO electrode with DNA probe, results in an increased R ct value of chip from 6.7 kX (curve i) to 53.8 kX (curve ii). Since, the QCdSe-LB/ITO electrode of the chip carries positive charge, owing to the ammonium group of TOPO capping agent, and the redox marker [Fe(CN) 6 ] 3À/4À ions are negatively charged, the repulsion is not experienced by the [Fe(CN) 6 ] 3À/4À ions from the electrode surface and thus, the R ct value of the chip is found to be low.…”

“…2,9,10 Direct electrochemical detection of DNA hybridization can be performed via electrochemical impedance spectroscopy (EIS), which monitors the increased surface charge on the chip as a result of DNA hybridization. 11,12 In this context, a diffusion-restriction model can be applied to miniaturized EIS based biochip nano-volume reactor. This model has been found to facilitate characterization of DNA hybridization events that contribute to both enhanced diffusion and charge transfer resistance.…”