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The development of photoelectrochemical (PEC) biosensors plays a critical role in enabling timely intervention and personalized treatment for cardiac injury. Herein, a novel approach is presented for the fabrication of highly sensitive PEC biosensor employing Bi 2 O 3 /MgIn 2 S 4 heterojunction for the ultrasensitive detection of heart fatty acid binding protein (H-FABP). The Bi 2 O 3 /MgIn 2 S 4 heterojunction, synthesized through in-situ growth of MgIn 2 S 4 on Bi 2 O 3 nanoplates, offers superior attributes including a larger specific surface area and more homogeneous distribution, leading to enhanced sensing sensitivity. The well-matched valence and conduction bands of Bi 2 O 3 and MgIn 2 S 4 effectively suppress the recombination of photogenerated carriers and facilitate electron transfer, resulting in a significantly improved photocurrent signal response. And the presence of the secondary antibody marker (ZnSnO 3 ) introduces steric hindrance that hinders electron transfer between ascorbic acid and the photoelectrode, leading to a reduction in photocurrent signal. Additionally, the competition between the ZnSnO 3 marker and the Bi 2 O 3 /MgIn 2 S 4 heterojunction material for the excitation light source further diminishes the photocurrent signal response. After rigorous repeatability and selectivity tests, the PEC biosensor exhibited excellent performance, and the linear detection range of the biosensor was determined to be 0.05 pg/mL to 100 ng/mL with a remarkable detection limit of 0.029 pg/mL (S/N = 3)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Highly responsive interface of semiconductor nanophotoelectrochemical materials provides a broad development prospect for the identification of low-abundance cancer marker molecules. This work innovatively proposes an efficient blank WO 3 /SnIn 4 S 8 heterojunction interface formed by self-assembly on the working electrode for interface regulation and photoregulation. Different from the traditional biomolecular layered interface, a hydrogel layer containing manganese dioxide with a wide light absorption range is formed at the interface after an accurate response to external immune recognition. The formation of the hydrogel layer hinders the effective contact between the heterojunction interface and the electrolyte solution, and manganese dioxide in the hydrogel layer forms a strong competition between the light source and the substrate photoelectric material. The process effectively improves the carrier recombination efficiency at the interface, reduces the interface reaction kinetics and photoelectric conversion efficiency, and thus provides strong support for target identification. Taking advantage of the process, the resulting biosensors are being explored for sensitive detection of human epidermal growth factor receptor 2, with a limit of detection as low as 0.037 pg/mL. Also, this study contributes to the advancement of photoelectrochemical biosensing technology and opens up new avenues for the development of sensitive and accurate analytical tools in the field of bioanalysis.

Bacterial infections, viral infections and autoimmune diseases pose a considerable threat to human health. Procalcitonin (PCT) has emerged as a biomarker for the detection of these diseases. To ensure accurate and reliable results, we propose a dual-mode approach that incorporates self-validation and self-correction mechanisms. Herein, we develop a dual-mode self-powered photoelectrochemical (PEC) and colorimetric sensor to determine PCT. The self-powered PEC sensor was constructed with a photoanode of spherical nanoflower-MoS 2 /Cu 2 ZnSnS 4 /Bi 2 S 3 material and a photocathode of CuInS 2 material. Ni 4 Cu 2 bimetallic hollow nanospheres (BHNs) possess superoxide dismutase and catalase performance, which facilitate superoxide anion radical (·O 2 - ) and H 2 O 2 circulating generation, promoting the separation of photogenerated electrons and holes to amplify photocurrent signal. Thus Ni 4 Cu 2 BHNs is used as a marker material for PEC sensor. Meanwhile, in colorimetric mode, Ni 4 Cu 2 BHNs converts blue oxTMB to a colourless TMB for colorimetric detection of PCT. Based on this principle, dual-mode determination of PCT with high sensitivity is achieved. The dual-mode method not only demonstrates outstanding properties and practicability, but also presents an effective, highly efficient and reliable method for detecting PCT., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

The interaction between the sensitive interfaces of photoelectrochemical (PEC) semiconductor nanomaterials and microscopic matter creates endless potential for the efficient detection of endocrine disruptor. This work presents the development of a high-efficiency PEC aptasensor for bisphenol A (BPA) monitoring based on Cu 3 BiS 3 sensitized CuV 2 O 6 nanocomposites with exceptional visible-light PEC activity. We implemented the integration of Cu 3 BiS 3 nanosheet photosensitizer to sensitize the CuV 2 O 6 nanowire structure that was synthesized utilizing a facile hydrothermal approach. The band gap alignment between Cu 3 BiS 3 and CuV 2 O 6 facilitated enduring PEC response yielding an efficient interfacial structure. The surface of the CuV 2 O 6 /Cu 3 BiS 3 electrode was modified with BPA aptamer, enabling specific binding with BPA and precise quantification of its content. The developed aptamer sensors possess a wide detection range of 5.00 × 10 -1 to 5.00 × 10 4 ng/mL, and a low detection limit of 1.60 × 10 -1 ng/mL (at S/N = 3). After undergoing 20 testing cycles and enduring long-term storage, the sensor maintained its stability and showcased excellent repeatability and reproducibility. This study presents a promising methodology for the detection of BPA in environmental settings., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Advanced bioelectronic detection based on the integration of modern optical electronics and biological systems has a broad prospect. The strategy of cathode signal amplification in self-powered photoelectrochemical (PEC) immunosensors with excellent performance is rarely reported in the field of immune analysis. Herein, the work demonstrates a self-powered PEC biosensor formed with BiOI photocathode and WO 3 /SnS 2 /ZnS photoanode, and CsPbBr 3 @COF-V was used as the photocathode signal quenching source for the quantitative monitoring of heart fatty acid binding protein (H-FABP). The high efficiency and stable self-powered biosensor formed not only provides continuous and powerful photocurrent response for bioanalysis through reasonable stepped band structure, but also effectively eliminates the interference of reducing substances. The quenching source CsPbBr 3 @COF-V greatly affects the photocurrent response due to steric hindrance, weak conductivity, competition with the substrate for dissolved oxygen and excitation light source. And the intervention of this key factor achieves multiple signal amplification effect and opens up an innovative vision for self-powered PEC immunosensor. Taking H-FABP as a representative analyte, the proposed signal amplification self-powered photoelectrochemical presents a broad linear range from 0.0005 to 150 ng/mL with the detection limit of 0.19 pg/mL., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Ultrasensitive and accurate physiological monitoring is of great significance for disease diagnosis and treatment. In this project, an efficient photoelectrochemical (PEC) split-type sensor on the basis of controlled release strategy was established with great success. Heterojunction formation between g-C 3 N 4 and Zn-doped CdS improved the visible light absorption efficiency, reduced carrier complexation, improved the PEC signal, and increased the stability of the PEC platform. Compared to the traditional model of immunosensors, the process of antigen-antibody specific binding was done in a 96 microplate, and the sensor separated the immune reaction from the photoelectrochemical conversion process, eliminating mutual interference. Cu 2 O nanocubes were used to label the second antibody (Ab 2 ), and acid etching using HNO 3 released a large amount of divalent copper ions, which exchanged cations with Cd 2+ in the substrate material, causing a sharp drop in photocurrent and improving the sensitivity of the sensor. Under the optimized experimental conditions, the PEC sensor based on the controlled release strategy for CYFRA21-1 target detection had a wide concentration linear range of 5 × 10 -5 to 100 ng/mL with a low detection limit of 0.0167 pg/mL (S/N = 3). This intelligent response variation pattern could also offer the possibility of additional clinical applications for other target detection., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Herein, a novel dual mode detection system of split-type photoelectrochemical (PEC) and visual immunoassay was developed to detect neuron specific enolase (NSE), which achieved simultaneous and reliable NSE detection due to the completely different signal readouts and transduction mechanism. Specifically, specific reactions of antigens and antibodies were performed in 96-microwell plates. Gold nanoparticle (Au NP)-loaded Fe 3 O 4 (Au@Fe 3 O 4 ) NPs were used as secondary antibody markers and signal regulators, which could produce a blue-colored solution in the presence of 3,3',5,5'-tetramethylbenzidine (TMB) and H 2 O 2 because of its peroxidase-like activity. Therefore, the visual detection of NSE was realized, making the results more intuitive. Meanwhile, the above biological process could also be used as part of the split-type PEC sensing platform. Oxidized TMB and Fe 3+ were consumptive agents of the electron donor, which both realized the double quenching of PEC signal generated by the SnO 2 /MgIn 2 S 4 /Zn 0.1 Cd 0.9 S composites. Owing to the waterfall band structure, SnO 2 /MgIn 2 S 4 /Zn 0.1 Cd 0.9 S composites partially absorb visible light and effectively inhibit the electron-hole recombination, thereby providing significantly enhanced and stable initial signal. On the basis of the multiple signal amplification strategy and the split-type mode, NSE could be sensitively detected with a low detection limit of 14.0 fg·mL -1 (S/N = 3) and a wide linear range from 50.0 fg·mL -1 to 50.0 ng·mL -1 .

Herein, a split-type immunoassay strategy instigated by cation exchange (CE) and changing the capacity of an electron donor in an electrolyte solution is optimized, namely, for differentiating the biological-specific binding assay and photoelectrochemical (PEC) analysis. MoSe 2 /CdSe, a Z-scheme heterojunction with efficient visible light absorption and a low recombination of carriers, is used as a photoelectrode substrate. Silver ions (Ag + ) as the initiator of CE are generated by the acidolysis of evenly loaded silver nanoparticles on mesoporous silica nanospheres (MSNs). The theoretical calculation and experimental results confirm that Ag + replaces Cd 2+ in CdSe and retains the crystal structure of MoSe 2 . However, this behavior destroys the perfectly matched heterojunction structure and introduces defects, which led to the reduction of the photocurrent response. In addition, ascorbate oxidase in combination with MSNs can be used as a consumptive agent of the electron donor, which further improves the sensitivity and reliability of the sensor. As a proof of principle, neuron-specific enolase was applied to elucidate the potential application of the PEC immunoassay in clinical diagnosis, and the obtained linear range of the sensor was from 0.0001 to 100 ng/mL with a detection limit of 28 fg/mL (S/N = 3).

A photoelectrochemical (PEC) biosensor capable of detecting cytokeratin 19 fragment 21-1 (CYFRA21-1) was optimized by taking advantage of the powerful conjugate repeats of horseradish peroxidase and tyramine (HRP-tyramine)-triggered enzymatic biocatalytic precipitation (BCP) on high-performance BiVO 4 /Ag 3 VO 4 /SnS 2 photoelectrodes. Compared with the ubiquitous BCP strategy, we identified a design supporting conjugate repeats generated by HRP and tyramine-triggered immeasurable insoluble precipitates in the presence of hydrogen peroxide and 4-chloro-1-phenol (4-CN), and the steric hindrance improved sensitivity. Moreover, by virtue of BiVO 4 , Ag 3 VO 4 , SnS 2 excellent level matching structure and chemical stability, a heterojunction (BiVO 4 /Ag 3 VO 4 /SnS 2 ) with high light absorption efficiency has been successfully prepared. The novel heterostructure system of BiVO 4 /Ag 3 VO 4 /SnS 2 with high detection current and low background signal exhibited high-performance PEC determination. Generally, the hitherto untapped biosensor resource realized the sensitive detection of CYFRA21-1 with a wide linear range from 50 fg/mL to 200 ng/mL, and a detection limit of 15 fg/mL, which illustrated the potential for biotechnological applications., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Herein, a smart competitive-type photoelectrochemical (PEC) sensor based on an antigen-down (Ag-down) format for procalcitonin (PCT) detection is proposed. A fullerene sensitized flower-like Sn 3 O 4 nano-structure is used as the photoactive platform, and FeS 2 is labeled on the secondary antibody as a signal adjusting element. The sensor exhibits excellent sensitivity and great stability.