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Ion-sensitive Field-effect Transistor (ion-sensitive + field-effect_transistor)

Distribution by Scientific Domains
Chemistry75%

Selected Abstracts

Analysis of Dopamine and Tyrosinase Activity on Ion-Sensitive Field-Effect Transistor (ISFET) Devices

CHEMISTRY - A EUROPEAN JOURNAL, Issue 26 2007
Ronit Freeman
Abstract Dopamine (1) and tyrosinase (TR) activities were analyzed by using chemically modified ion-sensitive field-effect transistor (ISFET) devices. In one configuration, a phenylboronic acid functionalized ISFET was used to analyze 1 or TR. The formation of the boronate,1 complex on the surface of the gate altered the electrical potential associated with the gate, and thus enabled 1 to be analyzed with a detection limit of 7×10,5,M. Similarly, the TR-induced formation of 1, and its association with the boronic acid ligand allowed a quantitative assay of TR to be performed. In another configuration, the surface of the ISFET gate was modified with tyramine or 1 to form functional surfaces for analyzing TR activities. The TR-induced oxidation of the tyramine- or 1 -functionalized ISFETs resulted in the formation of the redox-active dopaquinone units. The control of the gate potential by the redox-active dopaquinone units allowed a quantitative assay of TR to be performed. The dopaquinone-functionalized ISFETs could be regenerated to give the 1 -modified sensing devices by treatment with ascorbic acid. [source]

Detection of Explosives Using Field-Effect Transistors

ELECTROANALYSIS, Issue 20 2009
Etery Sharon
Abstract The gate surfaces of ion-sensitive field-effect transistor (ISFET) devices were functionalized with the ,-donor units, 6-hydroxydopamine (1) or 4-aminothiophenol (2). Concentration of trinitrotoluene, TNT, on the gate via ,-donor-acceptor interactions yields charge-transfer complexes that alter the gate potential. This enables the label-free analysis of TNT with a detection limit corresponding to 1×10,7,M. [source]

Analysis of Dopamine and Tyrosinase Activity on Ion-Sensitive Field-Effect Transistor (ISFET) Devices

CHEMISTRY - A EUROPEAN JOURNAL, Issue 26 2007
Ronit Freeman
Abstract Dopamine (1) and tyrosinase (TR) activities were analyzed by using chemically modified ion-sensitive field-effect transistor (ISFET) devices. In one configuration, a phenylboronic acid functionalized ISFET was used to analyze 1 or TR. The formation of the boronate,1 complex on the surface of the gate altered the electrical potential associated with the gate, and thus enabled 1 to be analyzed with a detection limit of 7×10,5,M. Similarly, the TR-induced formation of 1, and its association with the boronic acid ligand allowed a quantitative assay of TR to be performed. In another configuration, the surface of the ISFET gate was modified with tyramine or 1 to form functional surfaces for analyzing TR activities. The TR-induced oxidation of the tyramine- or 1 -functionalized ISFETs resulted in the formation of the redox-active dopaquinone units. The control of the gate potential by the redox-active dopaquinone units allowed a quantitative assay of TR to be performed. The dopaquinone-functionalized ISFETs could be regenerated to give the 1 -modified sensing devices by treatment with ascorbic acid. [source]

Dual-Gate Organic Field-Effect Transistors as Potentiometric Sensors in Aqueous Solution

ADVANCED FUNCTIONAL MATERIALS, Issue 6 2010
Mark-Jan Spijkman
Abstract Buried electrodes and protection of the semiconductor with a thin passivation layer are used to yield dual-gate organic transducers. The process technology is scaled up to 150-mm wafers. The transducers are potentiometric sensors where the detection relies on measuring a shift in the threshold voltage caused by changes in the electrochemical potential at the second gate dielectric. Analytes can only be detected within the Debye screening length. The mechanism is assessed by pH measurements. The threshold voltage shift depends on pH as ,Vth,=,(Ctop/Cbottom),×,58,mV per pH unit, indicating that the sensitivity can be enhanced with respect to conventional ion-sensitive field-effect transistors (ISFETs) by adjusting the ratio of the top and bottom gate capacitances. Remaining challenges and opportunities are discussed. [source]