Current‐Driven Organic Electrochemical Transistors for Monitoring Cell Layer Integrity with Enhanced Sensitivity

Abstract

In this progress report an overview is given on the use of the organic electrochemical transistor (OECT) as a biosensor for impedance sensing of cell layers. The transient OECT current can be used to detect changes in the impedance of the cell layer, as shown by Jimison et al. To circumvent the application of a high gate bias and preventing electrolysis of the electrolyte, in case of small impedance variations, an alternative measuring technique based on an OECT in a current-driven configuration is developed. The ion-sensitivity is larger than 1200 mV V -1 dec -1 at low operating voltage. It can be even further enhanced using an OECT based complementary amplifier, which consists of a p-type and an n-type OECT connected in series, as known from digital electronics. The monitoring of cell layer integrity and irreversible disruption of barrier function with the current-driven OECT is demonstrated for an epithelial Caco-2 cell layer, showing the enhanced ion-sensitivity as compared to the standard OECT configuration. As a state-of-the-art application of the current-driven OECT, the in situ monitoring of reversible tight junction modulation under the effect of drug additives, like poly-l-lysine, is discussed. This shows its potential for in vitro and even in vivo toxicological and drug delivery studies.

High‐Performance Bioelectronic Circuits Integrated on Biodegradable and Compostable Substrates with Fully Printed Mask‐Less Organic Electrochemical Transistors

“…To further assess the broad applicability of the proposed approach, fully printed OECTs were operated in a current‐driven configuration. [ 63,64 ] The current‐driven configuration overcomes the fundamental trade‐off between the sensitivity, operating range, and supply voltage, finding application in bioelectronics, including ion detection and real‐time monitoring of cell layers integrity. [ 24,25 ] Figure a shows the schematic circuit configuration and Figure 5b shows a photograph of various nominally identical OECTs printed on flexible foil and connected in a current‐driven configuration for high‐sensitivity ion detection.…”

Ion‐Selective Organic Electrochemical Transistors: Recent Progress and Challenges

“…When the supply voltage is ultralow as 0.2 V, this currentdriven OECT exhibits an average sensitivity of 243 mV dec −1 in the ion concentration range 10 −4 -10 −2 m and of 144 mV dec −1 in the range 10 −2 to 10 0 m. The bias current enables the currentdriven OECT to select the operating range and ensures the lowvoltage operation, thus the large transistor transconductance leads to the significant amplification in ion sensing. [92] However, the current-driven inverter-like configuration requires a read-out scheme and does not allow real-time ion sensing. To solve this problem, Romele et al further advanced the circuit topology into the integrated complementary OECTs consisting of a p-type (PEDOT:PSS based) and an n-type [poly(benzimidazobenzophenanthroline) based] OECT connected in series, which is a common approach used in digital electronic circuits to implement the NOT logic function (Figure 5e).…”

“…The bias current enables the current‐driven OECT to select the operating range and ensures the low‐voltage operation, thus the large transistor transconductance leads to the significant amplification in ion sensing. [ 92 ]…”

A sensitive platform for DNA detection based on organic electrochemical transistor and nucleic acid self-assembly signal amplification

“… 9 Therefore, by monitoring the changes in channel current, any charge transfer reaction that changes the surface potential of the gate electrode can be measured. 10–13 Moreover, OECTs can work stably in aqueous environments with a low operating voltage (<1 V), which is essential for DNA analysis. Thus, various OECT-based DNA sensors have been developed.…”