Reduced‐Graphene‐Oxide‐Based Needle‐Type Field‐Effect Transistor for Dopamine Sensing

Abstract

Owing to their intrinsic amplifying effect together with their temporal resolution, field‐effect transistors (FETs) are gaining momentum for the detection of different biomolecules at ultra‐low concentration levels such as, for example, neurotransmitters, particularly if the concentration level of the analyte is below the detection limit of commonly used electrochemical sensing methods. We demonstrate the fabrication of a spearhead reduced graphene oxide (rGO)‐based FET. The fabrication of the rGO‐based FET by means of an electrochemical pulse deposition technique enables a controllable process including both the deposition and reduction of the deposited graphene oxide between two carbon nanoelectrodes to form the channel of the rGO‐based FET. While using double‐barrel carbon nanoelectrodes, the as‐produced FETs offer new possibilities in terms of their applicability in very small volumes as well as the option of being positioned close to the desired measurement region. The fabrication process was evaluated and optimized to obtain rGO‐based FETs with high performance. The as‐fabricated devices were evaluated in terms of sensitivity and selectivity towards dopamine. The tested devices not only showed high sensitivity towards dopamine with a linear response ranging from 1 nM to 1 μM, but also maintained a similar sensing performance in the presence of 500 μM ascorbic acid.

Liquid-gated Field-effect-transistor Based on Chemically Reduced Graphene Oxide for Sensing Neurotransmitter Acetylthiocholine

“…7a) indicates that the higher ATCh concentration corresponding with the higher number of H + ions release and higher mobile charges on the FET/rGO channel. This result is in accordance with previous reports [14,43]. The limit of detection (LOD) value determines by five calibration points from the 0 mM to 0.8 mM concentration of ATCh.…”

“…The restored sp2 carbon atoms in reduced graphene oxide makes this material similar to graphene in term of electrical behaviors as well as other physical properties. In the same time, the residual functional groups remained after reduction process (if any) might even facilitate the immobilization of targeted molecules (i.e, biomolecules) for further applications in biosensors [14][15][16][17].…”

Two-Dimensional Field-Effect Transistor Sensors: The Road toward Commercialization

“…This direct exposure-induced charge transfer enabled real-time detection of 500 ppb dopamine molecules, showing its considerable promise in biochemical sensing. Other achievements in nonenzymatic detection have been made in apatamer or antibody modified 2D FET sensors, including GFET cortisol biosensors, , GFET biotin biosensors, GFET ascorbic acid biosensors, 2D MOF-FET gluconic acid biosensors, and others.…”

Micro- and nano-devices for electrochemical sensing

“…Moreover, differently from the above-mentioned architectures that have been historically dominated by the chip-like configuration, in the last years, spearhead FET structures were investigated, wherein both the transistor channel and gate are fabricated on the tip of micro- and nanoelectrodes. PPy [ 172 ], PEDOT:PSS [ 173 ], and graphene [ 174 ] have been studied as semiconductor materials. The main advantage of this structure is the possibility to accurately position the transistor-based sensors to map concentration gradients in space around a single living cell.…”