In Situ Engineering of S-Scheme Bi2O3/Zn3In2S6 Heterojunctions on Paper-Based Architectures for Dual-Mode Photoelectrochemical-Electrochemical Detection of Carcinoembryonic Antigen.
Aug 2026· Langmuir· Vol 42 32, pp.
23596-23606
· 0 citations· 65 references
Medicine
TL;DR
A highly sensitive dual-mode immunosensing platform, integrating photoelectrochemical (PEC) and electrochemical detection via the in situ architectural engineering of an S-scheme Bi2O3/Zn3In2S6 heterojunction directly onto cellulose fiber scaffolds, which represents a versatile architecture for the early diagnosis of diverse clinical biomarkers.
Abstract
The integration of multimodal signaling into paper-based analytical devices (PADs) provides a robust means to enhance reliability in point-of-care diagnostics. Herein, we demonstrate a highly sensitive dual-mode immunosensing platform, integrating photoelectrochemical (PEC) and electrochemical (EC) detection via the in situ architectural engineering of an S-scheme Bi2O3/Zn3In2S6 heterojunction directly onto cellulose fiber scaffolds. The spatial decoupling and synergistic charge migration inherent to the S-scheme interface significantly amplify the initial photocurrent response, providing a high-performance foundation for sensing. A sandwich-type bioconjugate assembly was implemented, utilizing SiO2/AuNPs nanoparticle-labeled secondary antibodies (SiO2/AuNPs-Ab2) as multifunctional signal modulators. The PEC signal experienced a dramatic, concentration-dependent attenuation owing to the synergistic interplay between the steric hindrance provided by SiO2 and the SPR effect provided by AuNPs. With a wide linear range of 0.001 to 100 ng mL-1, the platform exhibited excellent detection limits of 0.077 pg mL-1 (PEC) and 0.12 pg mL-1 (EC) for carcinoembryonic antigen (CEA) under optimized conditions. The dual-signal output enables intrinsic mutual validation, significantly mitigating false-positive risks. Given its modular design and exceptional sensitivity, this PADs-based heterojunction platform represents a versatile architecture for the early diagnosis of diverse clinical biomarkers.
Accurate biomarker detection is crucial for early and accurate disease diagnosis. Herein, a multiplexed biosensor capable of simultaneous electrochemical (EC) and photoelectrochemical (PEC) operation is fabricated using efficient, self-templated In2S3/CuInS2 (CIS) heterostructured nanotubes for the selective detection of bovine serum albumin (BSA). For the EC mode, the In2S3/CIS heterostructure exhibits a high differential pulse voltammetry (DPV) response arising from Cu+/Cu2+ electron transfer, alongside excellent peroxidase-mimetic activity toward H2O2. For the PEC mode, the n-p type semiconducting In2S3/CIS hollow nanotubes not only quench the photocurrent signals of photoactive ZnIn2S4 (ZIS) nanoflowers due to the competitive capture of light energy and consumption of electron donors; but also act as a peroxidase mimetic to generate insoluble precipitation. Furthermore, the steric hindrance effect from the In2S3/CIS heterostructure will further decrease the photocurrent signal output of ZIS. By integrating molecular imprinting technology, BSA can be specifically recognized and captured the imprinted cavities, leading to a significant decrease in both EC and photocurrent signals. Based on these multifunctional nanotubes, BSA is detected accurately with a wide linear range from 10-20 mg·mL-1 to 10-1 mg·mL-1 and a detection limit of 8.5 × 10-21 mg·mL-1. This multiplexed strategy provides a universal and efficient platform for clinical biomedicine and bioanalysis.
Hongyuan Shang, Wenjing Zhang, Jiaxuan Li et al.· Small· 0 citations
Herein, a novel signal-off photoelectrochemical (PEC) biosensor was rationally constructed by integrating a Bi2S3/RuO2 heterojunction with the multiple tetrahedral DNA nanonet (mTDN) for ultrasensitive and accurate lead ions detection. This photoactive Bi2S3/RuO2 composite was synthesized through a simple ultrasonic-assisted mixing method, in which the RuO2 not only functioned as an efficient electron conductor and a protective layer for Bi2S3, but also formed a typical p-n heterojunction with Bi2S3, effectively promoting the separation of photogenerated electron-hole pairs for achieving an extremely high initial photocurrent that twelve-times higher than individual component. Afterwards, the present of target lead ions (Pb2+) led to the specific DNAzyme cleavage on electrode, thus exposing abundant binding sites for immobilizing mTDN. Compared with traditional DNA nanostructures, the designed mTDN prone to form a continuous, dense, and uniform three-dimensional rigid network film, and thus endowed the effective obstructing of electronic transfer derived from non-conductive characteristic and spatial steric hindrance, significantly depressing the photocurrent for achieving sensitive and accurate Pb2+ detection. As a result, the proposed PEC biosensor exhibited excellent analytical performance with a low detection limit down to 0.82 fM (S/N = 3), providing a sensitive and reliable approach for environmental pollution monitoring and drinking water safety controlling.
The contamination of the environment with the sulfadiazine (SDZ) antibiotic poses a significant risk to human and animal health and contributes to the emergence of drug-resistant bacteria. Conventional detection methods are often time-consuming and require sophisticated instrumentation. Herein, we developed a sensitive SDZ detection method based on a high-performance photoelectrochemical (PEC) aptasensor. Using an iron oxide (Fe3O4) functionalized three-dimensional graphitic carbon nitride (3DCN) nanocomposite. The 3DCN substrate was initially prepared through supramolecular self-assembly employing an ionic liquid as a template, followed by thermal polycondensation. Then, Fe3O4 nanoparticles bearing abundant hydroxyl groups were covalently anchored onto the 3DCN matrix via a solvothermal method. The incorporation of Fe3O4 broadened the visible-light absorption, facilitating charge separation and transport, and acting as an effective electron donor. Operating in a "signal-on" mode, the proposed aptasensor exhibited excellent analytical performance with a broad linear range (0.1 nM-1000 nM), a low detection limit (215 pM), and outstanding selectivity, stability, and reproducibility. The practical applicability was successfully validated by detecting SDZ in river water and milk with recoveries of 98.1-99.8%. Overall, the Fe3O4/3DCN-based PEC aptasensor is a robust, sensitive, cost-effective with good potential for food safety, environmental monitoring, and public health protection.
Abdulkerim Oumer Mohammed, Wangui Peng, Xiangpeng Shi et al.· Bioelectrochemistry· 1 citation
The ultratrace determination of the typical "forever chemical" perfluorooctanoic acid (PFOA) is an urgent imperative due to its severe bioaccumulation and toxicity even at minute concentrations. However, its lack of redox and optical activity poses a significant challenge for conventional photoelectrochemical (PEC) sensing. Traditional PEC configurations rely on immobilizing recognition probes directly onto the solid electrode, an architecture that inherently suffers from restricted binding sites and poor reusability. To address this interfacial barrier, an electrode-immobilization-free (EIF) PEC aptasensor featuring a pH-driven dynamic heterojunction is designed for the subpicomolar detection of PFOA. In this architecture, hollow Fe2O3-TiO2 nanocages (Ti-Fe-O NCs) serve as the photoanode. Engineered as a bifunctional component, a 2D ZIF-L nanosheet acts as a dispersed carrier for the aptamer in the solution and functions as a mobile signal regulator. During the homogeneous recognition process, the specific binding between PFOA and the aptamer triggers the release of ZIF-L nanosheets. Driven by pH-regulated electrostatic affinity, the positively charged ZIF-L spontaneously migrates to and assembles onto the Ti-Fe-O surface. This target-responsive assembly facilitates the in situ construction of a Type-I heterojunction, generating a significantly enhanced photocurrent response. Consequently, the sensing platform achieves a broad linear range from 0.1 to 500 pM with an ultralow detection limit of 0.03 pM. Ultimately, by pioneering this homogeneous-to-heterogeneous signal transduction strategy, this highly sensitive platform provides a highly effective pathway for the environmental surveillance of inert forever chemicals at the subpicomolar level.
Ye Feng, Aijiao Guo, Guangqiu Lu et al.· Analytical Chemistry· 0 citations
Lower-background photoelectrochemical (PEC) bioanalysis is crucial for high-sensitivity biomolecule detection and early clinical disease screening by effectively eliminating matrix interference and reducing the background photocurrent noise. In this work, a novel, simple, label-free split-type PEC aptasensor was successfully constructed for interleukin-6 (IL-6) analysis based on electrospun Bi2O3 nanofibers (NFs) coupled with in situ grown iodine vacancy (IV) BiOI nanosheets (IV-BiOI/Bi2O3 NFs). The introduction of heterojunction interfaces and IV in BiOI/Bi2O3 NFs can synergistically regulate light absorption capacity, optimize electronic band structure, efficiently promote the separation and migration of photogenerated electron–hole pairs, and inhibit charge recombination, thus greatly enhancing PEC photocurrent response. Aptamer-capped mesoporous silica nanospheres encapsulate ascorbic acid to specifically recognize IL-6 (10.0 ng/mL), triggering large amounts of AA release. This boost-on photocurrent response yields a 30.9-fold enhancement versus the control group. By separating biorecognition reactions from photocurrent readout, the split-type strategy avoids electrode surface biomodification interference and achieves an ultralow background. The sensor presents a wide linear range, low detection limit (0.6 pg/mL), favorable selectivity, and stability and achieves reliable detection in real serum and sweat samples. This work provides a new paradigm for defective heterojunction-based PEC biosensing with label-free operation, simple fabrication, and a high signal-to-noise ratio.
The detection of low-abundance biomarkers in sweat with high sensitivity is essential for wearable health monitoring applications. However, the performance of conventional photoelectrochemical (PEC) sensors is constrained by their rigid substrates, inefficient charge separation, and limited miniaturization capability. This study develops a flexible PEC sensor for the detection of tumor necrosis factor-alpha (TNF-α) in sweat by integrating functional nanomaterials with a 3D-printed microdevice. A hole transport layer of graphene oxide (GO) is introduced onto the surface of bismuth sulfide (Bi2S3) nanorods via an ultrasound-assisted method, followed by the loading of a Fe-Co bimetal-organic framework (MOF) to form a Bi2S3@GO/MOF ternary composite. Crucially, beyond conventional performance metrics, we directly visualize and quantify the enhanced interfacial charge transfer of Bi2S3@GO/MOF at the microscale through scanning photoelectrochemical microscopy (SPECM) and intensity-modulated photocurrent spectroscopy (IMPS) techniques. Furthermore, the MOF structure provides anchoring sites for immobilizing biotinylated aptamers, enabling specific capture of TNF-α molecules. Finally, integration with a custom 3D-printed polydimethylsiloxane (PDMS) microdevice results in a miniaturized analysis system. Our work provides a blueprint for next-generation wearable diagnostics, merging fundamental PEC insight with scalable 3D-printed device engineering.
Tong Su, Sihan Yang, Lin Zhu et al.· ACS Sensors· 0 citations
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