Advanced organic bioelectronics enable smooth fusion between modern electronics and biological systems for better physiological monitoring and pathological examinations. Photon‐regulated ...bioelectronics are especially desirable due to the non‐contact impact, remote‐control, and even self‐powered operation. However, few studies have addressed the advanced photon‐enabled organic photoelectrochemical transistor (OPECT) biosensors capable of operation at zero gate bias. Here, on the basis of a hydrogel/graphene oxide hybrid (denoted as HGH), a multifunctional HGH‐gated OPECT biosensor is presented, which is exemplified by Ca2+‐triggered gelation on the CdS quantum dot (QD) photoelectrode linking with a sandwich immunoassay toward human IgG as the model target. Gelation of HGH on the CdS QD gate electrode can not only inhibit the interfacial mass transfer on the gate/electrolyte interface, but also significantly block the light absorption of CdS QDs, leading to the corresponding change of the channel currents of OPECT device. At zero gate bias, this OPECT biosensor exhibits high gain in response to light and good analytical performance for human IgG with a detection limit of 50 fg mL–1. Given the numerous intelligent hydrogel materials and their potential interactions with light, this work unveils a general platform for developing a new class of hydrogel‐gated OPECT bioelectronics and beyond.
A multifunctional hydrogel‐gated organic photoelectrochemical transistor biosensor is constructed using a Ca2+‐triggered hydrogel/graphene oxide hybrid on the CdS quantum dot photosensitive gate electrode linking with a sandwich immunoassay toward human IgG as the model target. The proposed biosensor exhibits high gain in response to light and good analytical performance at zero gate bias.
With reduced background and high sensitivity, photoelectrochemistry (PEC) may be applied as an intracellular nanotool and open a new technological direction of single‐cell study. Nevertheless, the ...present palette of single‐cell tools lacks such a PEC‐oriented solution. Here a dual‐functional photocathodic single‐cell nanotool capable of direct electroosmotic intracellular drug delivery and evaluation of oxidative stress is devised by engineering a target‐specific organic molecule/NiO/Ni film at the tip of a nanopipette. Specifically, the organic molecule probe serves simultaneously as the biorecognition element and sensitizer to synergize with p‐type NiO. Upon intracellular delivery at picoliter level, the oxidative stress effect will cause structural change of the organic probe, switching its optical absorption and altering the cathodic response. This work has revealed the potential of PEC single‐cell nanotool and extended the boundary of current single‐cell electroanalysis.
An integrated photocathodic nanotool was fabricated for dual‐functional intracellular drug delivery and evaluation of cellular oxidative stress in single live cell.
Reticular heterojunctions on the basis of metal–organic frameworks (MOFs) and covalent organic frameworks (COFs) have sparked considerable interest in recent research endeavors, which nevertheless ...have seldom been studied in optoelectronic biosensing. In this work, its utilization for organic photoelectrochemical transistor (OPECT) detection of the important cancer biomarker of neuron‐specific enolase (NSE) is reported. A MOF@COF@CdS quantum dots (QDs) heterojunction is rationally designed to serve as the photogating module against the polymeric channel. Linking with a sandwich complexing event, target‐dependent alternation of the photogate is achieved, leading to the changed photoelectric conversion efficiency as indicated by the amplified OPECT signals. The proposed assay demonstrates good analytical performance in detecting NSE, featuring a linear detection range from 0.1 pg mL−1 to 100 ng mL−1, with a detection limit of 0.033 pg mL−1.
Based on MIL‐68‐NH2@COFTP‐TA@CdS reticular heterojunction, a photoelectrode‐gated OPECT biosensor is presented, which is exemplified by the Cu2+‐triggered electron trap formation linking with a sandwich immunoassay. The reticular heterostructure enhances the regulation of the channel by the photosensitive gate. At zero gate bias, this OPECT biosensor exhibits high gain in response to light and good analytical performance for NSE.
Comprehensive Summary
We report herein the first observation of MOF nanozyme enabling dual‐functional photo‐induced charge transfer and biomimetic precipitation for advanced organic ...photoelectrochemical transistor (OPECT) bioanalysis. Specifically, Fe/Co‐MIL‐88, serving simultaneously as the semiconductor and nanozyme, was explored as a dual‐functional gating module in OPECT. Upon light illumination, it could accelerate the charge transfer of the photogate to produce enhanced photo‐induced voltage. Meanwhile, its catalytic property could efficiently produce biomimetic precipitation to block the nanopores in Fe/Co‐MIL‐88 and thus alter the device characteristics. The generic bioanalytical potential of such a rationale was then demonstrated with an aptasensing assisted by magnetic separation. This work represents the first exploration of biomimetic precipitation from MOF nanozymes for generic OPECT bioanalysis, it is expected to attract more interest in various nanozymes for novel optoelectronic bioanalytics.
In this work, we report a metal‐organic frameworks (MOF) nanozymes‐gated organic photoelectrochemical transistor (OPECT) biosensor. The bifunctional MOF could not only enable photo‐induced charge transfer but also catalyze biomimetic precipitation for advanced OPECT biosensing.
Although great advances have been achieved in the field of organic electrochemical transistor (OECT) biodetection, its fundamental sensing principles are still highly limited. Different from current ...dominating protocols for OECT biodetection, herein, the bio‐dependent regulation of light‐sensitive gate electrode for transducing the corresponding biological events is introduced. Exemplified by the enzymatically catalytic growth of gold nanoclusters to gold nanoparticles on the 3D TiO2/carbon fiber matrix gate electrode, the photoelectrochemistry of the hybrid gate photoanode shifts from the type‐II heterojunction to plasmonic type, rendering reduced photon‐to‐electron efficiency and thus decreased current response of the gate photoanode. By connecting to an alkaline phosphatase‐associated sandwich immunoassay event toward the representative analyte of C‐reactive protein, the model system exhibits target‐dependent tunability and good analytical performance at zero gate bias. A new sensing principle for OECT biodetection is manifested, and would spur more creativity to explore the rich light–matter interplay for advanced OECT biodetection.
Biologically modulating light‐sensitive photoanode of organic electrochemical transistor is achieved by biocatalytic growth of Au nanoclusters to Au nanoparticles on a TiO2 substrate, shifting the gate photoelectrochemistry from the type‐II heterojunction to plasmonic type. In the detection of C‐reactive protein antigen, the as‐proposed OECT biosensor exhibits good performance at zero gate bias.
Currently, one of important research directions of photoelectrochemical (PEC) bioanalysis is to exploit innovative photoactive species and their elegant implementations for selective detection and ...signal transduction. Different from existing candidates for photoelectrode development, this study, exemplified by the cationic dipeptide nanoparticles (CDNPs), reports the first demonstration of self-assembled peptide nanostructures (SAPNs) for the PEC bioanalysis. Specifically, the CDNPs were prepared as representative materials and then immobilized onto the indium tin oxide (ITO) electrode for the PEC differentiation of several commonly involved biomolecules such as ascorbic acid (AA) and l-cysteine. Significantly, the experimental results disclosed that the CDNPs possessed unique photocathodic responses and good analytical performance toward AA detection in terms of rapid response, high stability, and excellent selectivity. This work demonstrates the great potential of the large SAPN family for the future PEC bioanalysis development and has not been reported to our knowledge.
Though great advances are achieved in the area of organic electrochemical transistor (OECT) biosensors, general issues of shared electrolyte by the channel and gate electrode remain unsolved. On the ...other hand, to date binding‐free OECT detection of cellular membrane proteins is not reported. On the basis of the advanced technique of organic photoelectrochemical transistor (OPECT), herein the H‐cell‐supported OPECT device that can easily circumvent the issues of abovementioned shared electrolyte and its application toward binding‐free detection of membrane alkaline phosphatase (ALP) of HeLa cells is demonstrated. In such a configuration, usage of a Nafion perfluorinated membrane equipped H‐cell can well retain the ionic circuit of the device but prevent the diffusion of various molecules and minimize the possible interference. In the detection, ALP catalytic chemistry enables the sensitization of the TiO2 nanotubes electrode, triggering enhanced de‐doping of the poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) and thus resulting in altered channel currents proportionate to the membrane ALP. This work not only provides a new perspective for binding‐free detection of membrane protein but also represents a general protocol for H‐cell‐supported OECT/OPECT biosensors with enhanced accuracy.
H‐cell equipped with nafion perfluorinated membrane is developed to accommodate the organic photoelectrochemical transistor toward detection of membrane alkaline phosphatase activity with good performance. The integrated system can well retain the ionic circuit of transistor and block the directional diffusion of various molecules and thus circumvent the general interference issues of shared electrolyte by channel and gate.
Recently emerged liposomal photoelectrochemical (PEC) bioanalysis has brought new opportunities for biosensor development. This work presents the new concept of liposome-assisted enzymatic modulation ...of plasmonic photoelectrochemistry for PEC bioanalysis, which was exemplified by an Au nanoclusters (NCs)-sensitized nanoporous TiO
nanotubes (Au NC@TiO
NT) photoelectrode and an alkaline phosphatase (ALP)-loaded liposomal immunoassay of heart-type fatty acid binding protein in a 96-well plate. After sandwich immunorecognition and subsequent lysis treatment, enzymatically generated ascorbic acid by the released ALP was directed to reduce Au
into Au nanoparticles using the Au NCs as seeds, leading to the in situ change of the photoelectrochemistry of the electrode and corresponding reduction of the photocurrent. The depressed signal could be correlated with the target concentration with good analytical performance in terms of sensitivity and selectivity. This work features the liposome-assisted enzymatic modulation of plasmonic photoelectrochemistry, which provides a new protocol for general PEC bioanalysis development.
Dual-mode bioanalysis integrating photoelectrochemical (PEC) and other modes is emerging and allows signal cross-checking for more reliable results. Metal–organic frameworks (MOFs) have been shown to ...be attractive materials in various biological applications. This work presents the utilization of MOF encapsulation and stimuli-responsive decapsulation for dual-mode PEC and fluorescence (FL) bioanalysis. Photoactive dye methylene violet (MV) was encapsulated in zeolitic imidazolate framework-90 (ZIF-90) to form an MV@ZIF-90 hybrid material, and MV could be released by adenosine triphosphate (ATP)-induced ZIF-90 disintegration. The released MV not only had FL emission but also had a sensitization effect on the ZnIn2S4 (ZnInS) photoanode. Based on the MV-dependent sensitization effect and FL emission characteristic, a dual-mode PEC–FL strategy was established for ATP detection with low detection limits, that is, 3.2 and 4.1 pM for PEC and FL detection, respectively. This study features and will inspire the construction and implementation of smart MOF materials for dual-mode bioanalysis.
Metal-organic frameworks (MOFs) with unique physicochemical properties have found increasing applications in various fields including photoelectrochemical (PEC) sensors. This work describes a ...high-performance MOF-based PEC sensor towards tetracycline (TET), a kind of stable broad-spectrum antibiotics. Specifically, zeolitic imidazolate framework-8 (ZIF-8), on top of ZnIn2S4 nanosheets (ZIS)/fluorine-doped tin oxide (FTO), could interact with TET in a rapid and selective manner, causing the substantial reduction of the photocurrent signal. In TET detection, this sensor could quickly respond to TET with ultralow detection limit of 0.1 pM. In addition to a new TET sensor, this work is expected to inspire more interest in the development of advanced MOF-based PEC sensors.
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•A novel ZIF-8@ZnIn2S4/FTO photoelectrode was constructed for PEC detection of tetracycline.•The PEC sensor exhibited super-fast response toward tetracycline within one second.•This work has provided a new horizon for design and implementation of the advanced MOFs-based PEC sensor.
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