Chemical Redox Cycling in an Organic Photoelectrochemical Transistor: Toward Dual Chemical and Electronic Amplification for Bioanalysis

Abstract

The organic photoelectrochemical transistor (OPECT) has been proven to be a promising platform to study the rich light− matter−bio interplay toward advanced biomolecular detection, yet current OPECT is highly restrained to its intrinsic electronic amplification. Herein, this work first combines chemical amplification with electronic amplification in OPECT for dual-amplified bioanalytics with high current gain, which is exemplified by human immunoglobulin G (HIgG)-dependent sandwich immunorecognition and subsequent alkaline phosphatase (ALP)-mediated chemical redox cycling (CRC) on a metal−organic framework (MOF)-derived BiVO 4 /WO 3 gate. The target-dependent redox cycling of ascorbic acid (AA) acting as an effective electron donor could lead to an amplified modulation against the polymer channel, as indicated by the channel current. The as-developed bioanalysis could achieve sensitive HIgG detection with a good analytical performance. This work features the dual chemical and electronic amplification for OPECT bioanalysis and is expected to stimulate further interest in the design of CRC-assisted OPECT bioassays.

Tailoring Charge Flow in Carbon-Defective Cu-MOF with Pd Nanoparticles: A Boost for Visible Light Organic Photoelectrochemical Transistor in Bioanalysis

“…Under visible light illumination, the alteration of the gate potential results in a sensitive change in I DS . In essence, the OPECT device operates on a photovoltage at the gate/electrolyte interface, enabling photochemical modulation of the channel . In more specific terms, in the dark state, PEDOT + maintains its oxidation state, giving the channel a high conductivity.…”

“…As shown in Figure 7A, under the same illumination and working electrode, the photocurrent intensity (I G = I G,light �I G,dark ) of the traditional PEC method is 0.15 μA, In essence, the OPECT device operates on a photovoltage at the gate/electrolyte interface, enabling photochemical modulation of the channel. 34 In more specific terms, in the dark state, PEDOT + maintains its oxidation state, giving the channel a high conductivity. However, under visible light, the presence of V photo induces cation injection into the PEDOT + :PSS − channel, producing PEDOT 0 , resulting in a low conductivity of the channel.…”

Dual Engine Boosts Organic Photoelectrochemical Transistor for Enhanced Modulation and Bioanalysis

“…Based on the fusion between organic electrochemical transistor (OECT) − and photoelectrochemistry (PEC), − the newly emerged organic photoelectrochemical transistor (OPECT) − composing three terminals of photoresponsive gate (G), source (S), and drain (D) have shown substantial potential in the development of next-generation organic devices with intrinsic signal amplification, temporal-spatial light controllability, and diverse applications in, e.g., bioanalysis, , optoelectronics, − and neuromorphic engineering. , Principally, according to different signaling mechanisms stemming from the pristine doping state of the conducting channels, existing OPECT operations could be divided into depletion and accumulation modes. − Light impact on specific photogates could induce additional photopotential and alter the potential distribution of the two solid–liquid interfaces. − Previous studies have revealed that photoanodes generating positive photovoltage are more suitable for depletion-mode channels, while photocathodes generating negative photovoltage are more suitable for accumulation-mode channels. These studies hinted at an either-or situation yet ignored another possibility: could both the photoanode and photocathode be simultaneously utilized for enhanced OPECT bioanalysis?…”