Enhancing Potentiometric Response of Electrochemical Sensor Using Modified Ion-Sensitive Transistor

In this work, we present a novel combination of solid-state ion-selective electrode and field effect transistor (FET) integrated on same platform. Thus, creating an extended gate field effect transistor (EGFET). We have built an electrochemical sensing unit comprised of all solid-state electrodes, an Ag/AgCl reference electrode and ionophore coated gold electrode. Unlike any of the earlier reports, all the electrodes are integrated with a FET in a single plane of the printed circuit board (PCB), hence mitigating the issues of separate wire bonding or external connection between the sensing element and the transducer by using PCB traces. In this work, we demonstrate for the first time, the use of ion sensitive electrode (ISE) in EGFET configuration without degrading the linearity and sensitivity due to the external voltage bias. Potentiometric measurement on our K + ISE shows near Nernstian limit sensitivity (49 mV/decade), low concentration for the limit of detection (10 −6 M), and linearity over a large range of detection(10 −4 M to 1 M).

Download Full-text

A solid-state reference electrode based on bilayer coating with poly(p,p'-biphenol) and polyimide films for the gate of field effect transistor.

Analytical Sciences ◽

10.2116/analsci.5.729 ◽

1989 ◽

Vol 5 (6) ◽

pp. 729-734 ◽

Cited By ~ 6

Author(s):

Noboru OYAMA ◽

Takeo OHSAKA ◽

Shin IKEDA ◽

Katsumi OKUAKI

Keyword(s):

Solid State ◽

Field Effect ◽

Field Effect Transistor ◽

Reference Electrode ◽

Polyimide Films ◽

Bilayer Coating ◽

State Reference ◽

Effect Transistor

Download Full-text

Stable Thin-Film Reference Electrode on Plastic Substrate for All-Solid-State Ion-Sensitive Field-Effect Transistor Sensing System

IEEE Electron Device Letters ◽

10.1109/led.2017.2732352 ◽

2017 ◽

Vol 38 (10) ◽

pp. 1469-1472 ◽

Cited By ~ 10

Author(s):

Qiaofeng Li ◽

Wei Tang ◽

Yuezeng Su ◽

Yukun Huang ◽

Sai Peng ◽

...

Keyword(s):

Thin Film ◽

Solid State ◽

Field Effect ◽

Field Effect Transistor ◽

Reference Electrode ◽

Plastic Substrate ◽

Sensing System ◽

Effect Transistor

Download Full-text

A field effect transistor as a solid-state reference electrode

Analytica Chimica Acta ◽

10.1016/s0003-2670(01)93361-6 ◽

1978 ◽

Vol 101 (2) ◽

pp. 247-252 ◽

Cited By ~ 50

Author(s):

Pierre A. Comte ◽

Jiří Janata

Keyword(s):

Solid State ◽

Field Effect ◽

Field Effect Transistor ◽

Reference Electrode ◽

State Reference ◽

Effect Transistor

Download Full-text

Ultrasensitive and Highly Selective Graphene-Based Field-Effect Transistor Biosensor for Anti-Diuretic Hormone Detection

Sensors ◽

10.3390/s20092642 ◽

2020 ◽

Vol 20 (9) ◽

pp. 2642 ◽

Cited By ~ 1

Author(s):

Reena Sri Selvarajan ◽

Ruslinda A. Rahim ◽

Burhanuddin Yeop Majlis ◽

Subash C. B. Gopinath ◽

Azrul Azlan Hamzah

Keyword(s):

Human Serum ◽

Field Effect ◽

Field Effect Transistor ◽

Limit Of Detection ◽

The Body ◽

Artificial Kidney ◽

Diuretic Hormone ◽

Effect Transistor ◽

Surface Modified ◽

Relative Change

Nephrogenic diabetes insipidus (NDI), which can be congenital or acquired, results from the failure of the kidney to respond to the anti-diuretic hormone (ADH). This will lead to excessive water loss from the body in the form of urine. The kidney, therefore, has a crucial role in maintaining water balance and it is vital to restore this function in an artificial kidney. Herein, an ultrasensitive and highly selective aptameric graphene-based field-effect transistor (GFET) sensor for ADH detection was developed by directly immobilizing ADH-specific aptamer on a surface-modified suspended graphene channel. This direct immobilization of aptamer on the graphene surface is an attempt to mimic the functionality of collecting tube V 2 receptors in the ADH biosensor. This aptamer was then used as a probe to capture ADH peptide at the sensing area which leads to changes in the concentration of charge carriers in the graphene channel. The biosensor shows a significant increment in the relative change of current ratio from 5.76 to 22.60 with the increase of ADH concentration ranging from 10 ag/mL to 1 pg/mL. The ADH biosensor thus exhibits a sensitivity of 50.00 µA· ( g / mL ) − 1 with a limit of detection as low as 3.55 ag/mL. In specificity analysis, the ADH biosensor demonstrated a higher current value which is 338.64 µA for ADH-spiked in phosphate-buffered saline (PBS) and 557.89 µA for ADH-spiked in human serum in comparison with other biomolecules tested. This experimental evidence shows that the ADH biosensor is ultrasensitive and highly selective towards ADH in PBS buffer and ADH-spiked in human serum.

Download Full-text

Two-Channel Graphene pH Sensor Using Semi-Ionic Fluorinated Graphene Reference Electrode

Sensors ◽

10.3390/s20154184 ◽

2020 ◽

Vol 20 (15) ◽

pp. 4184

Author(s):

Dae Hoon Kim ◽

Woo Hwan Park ◽

Hong Gi Oh ◽

Dong Cheol Jeon ◽

Joon Mook Lim ◽

...

Keyword(s):

Electrolyte Solution ◽

Field Effect ◽

Field Effect Transistor ◽

Ph Value ◽

Characteristic Curve ◽

Reference Electrode ◽

Reference Channel ◽

Buffer Solution ◽

Positive Direction ◽

Effect Transistor

A reference electrode is necessary for the working of ion-sensitive field-effect transistor (ISFET)-type sensors in electrolyte solutions. The Ag/AgCl electrode is normally used as a reference electrode. However, the Ag/AgCl reference electrode limits the advantages of the ISFET sensor. In this work, we fabricated a two-channel graphene solution gate field-effect transistor (G-SGFET) to detect pH without an Ag/AgCl reference electrode in the electrolyte solution. One channel is the sensing channel for detecting the pH and the other channel is the reference channel that serves as the reference electrode. The sensing channel was oxygenated, and the reference channel was fluorinated partially. Both the channels were directly exposed to the electrolyte solution without sensing membranes or passivation layers. The transfer characteristics of the two-channel G-SGFET showed ambipolar field-effect transistor (FET) behavior (p-channel and n-channel), which is a typical characteristic curve for the graphene ISFET, and the value of VDirac was shifted by 18.2 mV/pH in the positive direction over the range of pH values from 4 to 10. The leakage current of the reference channel was 16.48 nA. We detected the real-time pH value for the two-channel G-SGFET, which operated stably for 60 min in the buffer solution.

Download Full-text