MXene-Enhanced Bi₂S₃/CdIn₂S₄ Heterojunction Photosensitive Gate for DEHP Detection in a Signal-On OPECT Aptamer Biosensor

Abstract

Organic electrochemical transistors with signal amplification and good stability are expected to play a more important role in the detection of environmental pollutants. However, the bias voltage at the gate may have an effect on the activity of vulnerable biomolecules. In this work, a novel organic photoelectrochemical transistor (OPECT) aptamer biosensor was developed for di(2-ethylhexyl) phthalate (DEHP) detection by combining photoelectrochemical analysis with an organic electrochemical transistor, where MXene/Bi 2 S 3 /CdIn 2 S 4 was employed as a photoactive material, target-dependent DNA hybridization chain reaction was used as a signal amplification unit, and Ru(NH 3 ) 63+ was selected as a signal enhancement molecule. The poly(3,4ethylenedioxythiophene):poly(styrenesulfonate)-based OPECT biosensor modulated by the MXene/Bi 2 S 3 /CdIn 2 S 4 photosensitive material achieved a high current gain of nearly a thousand times at zero bias voltage. The developed signal-on OPECT sensing platform realized sensitive and specific detection of DEHP, with a detection range of 1−200 pM and a minimum detection limit of 0.24 pM under optimized experimental conditions, and its application to real water samples was also evaluated with satisfactory results. Hence, the construction of this OPECT biosensing platform not only provides a promising tool for the detection of DEHP but also reveals the great potential of the OPECT application for the detection of other environmental toxins.

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?…”

Photoelectrochemical/Colorimetric Dual-Mode Specific Detection of Staphylococcus aureus Based on the Enzymatic Reaction Triggered by Catalase from Lysed Bacteria

“…Among them, PEC biosensors are considered a promising strategy due to the detection signal and excitation signal in different energy forms, offering lower background signals and enhanced sensitivity . Unlike electrochemical sensing, which relies on specific potentials for signal generation, PEC is less dependent on external potentials due to the strong redox properties of electron–hole pairs in photoactive materials, reducing damage to biomolecules and minimizing the occurrence of side reactions . On the other hand, colorimetry does not require complex instrumentation and can be conveniently observed with the naked eyes, making it a cost-effective and rapid approach .…”