The Integration of Reference Electrode for ISFET Ion Sensors Using Fluorothiophenol-Treated rGO.

Ion-sensitive field-effect transistors (ISFETs) detect specific ions in solutions that enable straightforward, fast, and inexpensive sensors compared to other benchtop equipment. However, a conventional reference electrode (RE) such as Ag/AgCl is limited on the miniaturization of the sensor. We introduce reduced graphene oxide (rGO), which serves as a new RE, when fluorinated (F-rGO) using fluorothiophenol through the π-π interaction.

Two-Dimensional Disposable Graphene Sensor to Detect Na Ions.

The monitoring of Na ions distributed in the body has been indirectly calculated by the detection of Na ions in urine. We fabricated a two-dimensional (2D) Na ion sensor using a graphene ion-sensitive field-effect transistor (G-ISFET) and used fluorinated graphene as a reference electrode (FG-RE). We integrated G-ISFET and FG on a printed circuit board (PCB) designed in the form of a secure digital (SD) card to fabricate a disposable Na ion sensor.

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

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.

Artificial Differentiation of Hippocampal Neurons by Electrical Stimulation on Graphene Electrode.

Electrical stimulation therapy is a promising method for treating neurological diseases. This method induces the activity and differentiation of nerve cells by the direct or indirect transmission of an electrical signal through biomedical electrodes. We demonstrated the efficacy of a graphene sheet as a bioelectrode to differentiate neurites from hippocampal neuron, through electrical stimulation.

Detection of Alpha-Fetoprotein in Hepatocellular Carcinoma Patient Plasma with Graphene Field-Effect Transistor.

The detection of alpha-fetoprotein (AFP) in plasma is important in the diagnosis of hepatocellular carcinoma (HCC) in humans. We developed a biosensor to detect AFP in HCC patient plasma and in a phosphate buffer saline (PBS) solution using a graphene field-effect transistor (G-FET). The G-FET was functionalized with 1-pyrenebutyric acid -hydroxysuccinimide ester (PBASE) for immobilization of an anti-AFP antibody.

Effect of graphene on growth of neuroblastoma cells.

The unique properties of graphene have earned much interest in the fields of materials science and condensed-matter physics in recent years. However, the biological applications of graphene remain largely unexplored. In this study, we investigated the conditions and viability of a cell culture exposed to graphene onto glass and SiO2/Si, using a human nerve cell line, SH-SY5Y.