Selective Ion Detection with Integrated Organic Electrochemical Transistors

Accurate sensing of ion concentrations in body fluids is of importance to monitor cell functions, and any deviation of the concentration serves as a warning sign of pathophysiological conditions. Here, a fabrication approach for an integrated device consisting of two electrochemical transistors, capable of selective simultaneous detection between potassium and sodium ions in an analyte is demonstrated. A common in-plane gate electrode is integrated in the substrate, enabling the fabrication of micro-scale ion sensors for biomedical applications. The approach is versatile and can be extended to include numerous ion-selective transistors on a chip in order to meet the demand for simultaneous sensing of multiple ions

Monitoring Reversible Tight Junction Modulation with a Current-Driven Organic Electrochemical Transistor

The barrier functionality of a cell layer regulates the passage of nutrients into the blood. Modulating the barrier functionality by external chemical agents like poly-l-lysine (PLL) is crucial for drug delivery. The ability of a cell layer to impede the passage of ions through it and therefore to act as a barrier, can be assessed electrically by measuring the resistance across the cell layer. Here, an organic electrochemical transistor (OECT) is used in a current-driven configuration for the evaluation of reversible modulation of tight junctions in Caco-2 cells over time. Exposure to low and medium concentrations of PLL initiates reversible modulation, whereas a too high concentration induces an irreversible barrier disruption due to nonfunctional tight junction proteins. The results demonstrate the suitability of OECTs to in situ monitor temporal barrier modulation and recovery, which can offer valuable information for drug delivery applications