Label‐free electrical detection of DNA by means of field‐effect nanoplate capacitors: Experiments and modeling

Abstract

Label-free electrical detection of consecutive deoxyribonucleic acid (DNA) hybridization/denaturation by means of an array of individually addressable field-effect-based nanoplate siliconon-insulator (SOI) capacitors modified with gold nanoparticles (Au-NP) is investigated. The proposed device detects charge changes on Au-NP/DNA hybrids induced by the hybridization or denaturation event. DNA hybridization was performed in a high ionic-strength solution to provide a high hybridization efficiency. On the other hand, to reduce the screening of the DNA charge by counter ions and to achieve a high sensitivity, the sensor signal induced by the hybridization and denaturation events was measured in a low ionic-strength solution. High sensor signals of about 120, 90, and 80 mV were registered after the DNA hybridization, denaturation, and re-hybridization events, respectively. Fluorescence microscopy has been applied as reference method to verify the DNA immobilization, hybridization, and denaturation processes. An electrostatic charge-plane model for potential changes at the gate surface of a nanoplate field-effect sensor induced by the DNA hybridization has been developed taking into account both the Debye length and the distance of the DNA charge from the gate surface.

Degradation of thin poly(lactic acid) films: Characterization by capacitance–voltage, atomic force microscopy, scanning electron microscopy and contact-angle measurements

“…Such EIS sensors are simple in layout, easy and low-cost in fabrication (usually no photolithographic process steps and complicated encapsulation procedures are required). In previous experiments, EIS sensors have been applied for the detection of pH [16], ion concentration [17,18], enzymatic reactions [19,20] and enzyme-logic gates [21], charged macromolecules [22] and nanoparticles [23]. In general, the functioning mechanism of field-effect (bio-)chemical sensors is based on the effect of charge or potential changes at the interface electrolyte/gate insulator induced by the particular analyte.…”

An Analytical Approach to Calculate the Charge Density of Biofunctionalized Graphene Layer Enhanced by Artificial Neural Networks

“…Liquid-gated FETs (LGFET) are composed of graphene films which act as conducting channels, where the electrochemical potential of the solution is controlled with a gate electrode [14,24]. The ability to detect the hybridization of target DNA to the probe DNA is the main function of LGFETs.…”

“…Conductance of FETs can be tuned by an external electrical field induced by the gate voltage, provided that graphene has a tunable carrier density [12]. Graphene-based DNA sensors have been reported experimentally by researchers [13][14][15][16][17][18][19][20]. Lately, considerable research work has been put into the improvement of label-free DNA and protein biosensors [20,21].…”

Detection of 25-Hydroxyvitamin D3 with an Enzyme modified Electrode

“…The two electrons necessary for the catalytic cycle are supplied by the electron donor NADPH and transferred via two electron-transfer proteins, NADPH-adrenodoxin reductase (ADR) and adrenodoxin (ADX) [7]. This pathway could potentially be utilized using electrochemical methods to detect NADPH/NADP + redox couple on an electrode ( Figure 1A) [16][17][18]. As an alternative, non-native redox mediators can be used for electron delivery and electrochemical quantification of enzymatic activity ( Figure 1B).…”