Nonoptical Detection of Allergic Response with a Cell-Coupled Gate Field-Effect Transistor

Abstract

In this study, we report the label-free and reliable detection of allergic response using a cell-coupled gate field-effect transistor (cell-based FET). Rat basophilic leukemia (RBL-2H3) cells were cultured as a signal transduction interface to induce allergic reaction on the gate oxide surface of the FET, because IgE antibodies, which bind to Fcε receptors at the RBL-2H3 cell membrane, are specifically cross-linked by allergens, resulting in the allergic response of RBL-2H3 cells. In fact, the surface potential at the FET gate decreased owing to secretions such as histamine from the IgE-bound RBL-2H3 cells, which reacted with the allergen. This is because histamine, as one of the candidate secretions, shows basicity, resulting in a change in pH around the cell/gate interface. That is, the RBL-2H3-cell-based FET used in this study was originally from an ion-sensitive FET (ISFET), whose oxide surface (TaO) with hydroxyl groups is fully responsive to pH on the basis of the equilibrium reaction. The allergic response of RBL-2H3 cells on the gate was also confirmed by estimating the amount of β-hexosaminidase released together with histamine and was analyzed using the electrical properties based on an inflammatory response of secreted histamine with the vascular endothelial cell-based FET. Thus, the allergic responses were monitored in a nonoptical and real-time manner using the cell-based FETs with the cellular layers on the gate, which reproduced the in vivo system and were useful for the reliable detection of the allergic reaction.

Elucidation of interfacial pH behaviour at the cell/substrate nanogap forin situmonitoring of cellular respiration

“…In our previous works, the cellular respiration activities of rat pancreatic β cells, a single mouse embryo, and bovine chondrocytes or the allergic responses of mast cells on a gate were monitored noninvasively, quantitatively, and continuously as the change in pH using cell-coupled gate ISFET sensors. [4][5][6][7] Additionally, similar electrical responses were also obtained for other living cells, as shown in section S1 (ESI †). Since the gate insulator used as an electrode usually consists of an oxide with hydroxyl groups at the surface in a solution, the ISFET sensors are sensitive to changes in the concentration of positively charged hydrogen ions based on the equilibrium reaction (-OH 2 + ↔ -OH ↔ -O − ); consequently, they can be utilized as pH sensors ( Fig.…”

Biocompatible and flexible paper-based metal electrode for potentiometric wearable wireless biosensing

“…As a result, a change in the interfacial potential between the solution and the oxide membrane surface is output as the Nernstian response for the change in pH, which is ideally calculated as 59.2 mV/pH at 25°C. Cellular respiration activities were monitored at a cell/ gate nanogap interface using a pH-sensitive FET in a real-time and noninvasive manner [21][22][23][24][25][26][27]. When polyvinyl chloride (PVC)-based ISMs with ionophores are coated on a gate insulator, the Nernstian response is similarly obtained for the change in the potential at the solution/ISM interface with ions of various concentrations (e.g., Na + and K + ) [1,16,18,19].…”

Electropolymerized Poly(toluidine blue O) Film Electrode for Potentiometric Biosensing

“…Additionally, the spikelike structure is considered to have contributed to the improved pH responsivity and sensitivity. Basically, the pH response of the oxide gate surface should be Nernstian when potentiometric sensors are used; (28,29) the Nernstian response is calculated to be 59.1 mV/pH at 25 ℃ using…”