Organic Electrochemical Transistors: An Emerging Technology for Biosensing

Abstract

Recent research demonstrates the viability of organic electrochemical transistors (OECTs) as an emergent technology for biosensor applications. Herein, a comprehensive summary is provided, highlighting the significant progress and most notable advances within the field of OECT‐based biosensors. The working principles of an OECT are detailed, with specific attention given to the current library of organic mixed ionic‐electronic conductor (OMIEC) channel materials utilized in OECT biosensors. The application of OECTs for metabolite, ion, neuromorphic, electrophysiological, and virus sensing as well as immunosensing is reported, detailing the breadth and scope of OECT‐based biosensors. Furthermore, an outlook and perspective on synthetic molecular design of future channel materials, specifically designed for OECT biosensors, is provided. The development of optimized channel materials, creative device architectures, and operational nuances will set the stage for OECT‐based biosensors to thrive and accelerate their clinical prevalence in the near future.

Donor Functionalization Tuning the N‐Type Performance of Donor–Acceptor Copolymers for Aqueous‐Based Electrochemical Devices

“…Since the CV measurement demonstrated n‐type characteristics of NDI copolymers in aqueous media, the mixed electronic/ionic transport properties of NDI copolymers were studied as channel materials by fabricating OECTs. The key figure of merit, transconductance g m , at saturation conditions for OECTs materials is expressed as Equation (3) [ 55 ] $$\[ \begin{array}{*{20}{c}}{{g_{{\rm{m}} = }}\frac{{Wd}}{L}\mu C * \left( {{V_{{\rm{TH}}}} - {V_{\rm{G}}}} \right)}\end{array} \]$$where W is the channel width, d is the channel depth and L represents the channel length; V G is the gate voltage and V TH is the threshold voltage; μ is the charge‐carrier mobility and C * is the volume capacitance. [ 56 ] The value of µ C * is often used for evaluating the electronic/ionic conduction properties of the channel material.…”

“…Since the CV measurement demonstrated n-type characteristics of NDI copolymers in aqueous media, the mixed electronic/ionic transport properties of NDI copolymers were studied as channel materials by fabricating OECTs. The key figure of merit, transconductance g m , at saturation conditions for OECTs materials is expressed as Equation (3) [55] g…”

“…[56] The value of µC* is often used for evaluating the electronic/ionic conduction properties of the channel material. [55] The OECTs output and transfer characteristics are displayed in Figure 4 and the corresponding performance data of OECTs are summarized in Table 2. gNDI-FBT with weak donor exhibited the best device characteristics among three NDI copolymers.…”

PEDOT Composite with Ionic Liquid and Its Application to Deformable Electrochemical Transistors

“…Organic electrochemical transistors (OECTs) have received considerable attention for their wearable skin-inspired electronics and implantable bioelectronics [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. They can operate in wet environments such as biofluids or cells because of their ionic conductive electrolyte layer and soft channel polymers.…”

Organic electrochemical transistor as an on-site signal amplifier for electrochemical aptamer-based sensing

“…However, the upper limit for the enhancement of the surface area and the sensitivity can only be improved dozens of times at most (14). Another strategy to enhance sensitivity is through amplification, typically by implementing a transistor (17, 18). Among different types of transistors, organic electrochemical transistors (OECTs) have gained particular attention (19, 20).…”