Search

Studies have shown that non–small cell lung cancer is a malignant disease with a large number of malignant tumors. As a result, it is widely recognized by researchers that achieving sensitive detection of the non–small cell lung cancer biomarker cytokeratin 19 fragment (CYFRA21–1) is essential. Combining the advantages of photoelectrochemical (PEC) sensors, a polarity reversal transition PEC sensor was successfully constructed to achieve sensitive detection of CYFRA21–1. An s-type heterojunction Bi 2 WO 6–ε /BiO 1–δ I containing oxygen vacancies is used for the construction of this sensor and can be used to enhance the electron-hole mobility by an internal electric field. Incorporating Ag@PDA serves as a pivotal linkage, a novel and less applied linker. The addition of Ag@PDA provides more active sites for better linkage. The selected marker is proportional Cd 1–x Zn x S, which can obtain the best photoelectric response by optimizing the feeding ratio of Cd and Zn. The synergistic effect of oxygen vacancies–driven and proportional Cd 1–x Zn x S mediated signal reversal PEC sensor can achieve sensitive detection of CYFRA21–1 with a detection range of 1 pg/mL ∼ 100 ng/mL and a detection limit of 0.51 pg/mL. This research may open up a new promising PEC strategy for some other antigen proteins analysis. [Display omitted] • Oxygen vacancies in Bi 2 WO 6-ε /BiO 1-δ I enable enhanced photocurrent signals. • Optimization of feeding ratio and selection of Cd 0.66 Zn 0.34 S as a marker. • Polarity reversal strategy for sensitive detection of CYFRA21–1. [ABSTRACT FROM AUTHOR]

The incidence of esophageal cancer is positively associated with fumonisin contamination. It is necessary to develop methods for the rapid detection of fumonisins. In this work, a self-powered photoelectrochemical aptamer sensor based on ZnIn 2 S 4 /WO 3 photoanode and Au@W–Co 3 O 4 photocathode is proposed for the sensitive detection of fumonisin B1 (FB1). Among them, under visible light irradiation, the Z-type heterostructure of ZnIn 2 S 4 /WO 3 acts as a photoanode to improve the electron transfer rate, which contributes to the enhancement of the photocathode signal and lays the foundation for a wider detection range. The Au@W–Co 3 O 4 photocathode as a sensing interface reduces the probability of false positives (comparison of anode sensing platforms). The PEC sensor has a good working performance in the detection range (10 pg/mL-1000 ng/mL) with a detection limit of 2.7 pg/mL (S/N = 3). In addition, the sensor offers good selectivity, stability and excellent recoveries in real sample analysis. This work is expected to play a role in the field of analyzing environmental toxins. [ABSTRACT FROM AUTHOR]

Lead ion (Pb2+) is one of the heavy metal contaminants within the environment, which can seriously affect biological health. Thus, it is very important to detect lead ions, especially exceeding the standard concentration (100 ng/mL). In this work, we have developed a photoelectrochemical (PEC) aptamer sensor with Z-scheme Fe 2 O 3 /g-C 3 N 4 heterojunction as a substrate material for sensitive detection of Pb2+. Specifically, Fe 2 O 3 /g-C 3 N 4 is employed as a substrate with a powerful and stable photocurrent response. Au and DNA-1 connected to the substrate material via the Au-S bond and increased the electron conduction. Marking DNA-2 with ZnO effectively reduced the light absorption intensity resulting in a lower photocurrent response. Surprisingly, the Pb2+ PEC sensor showed good linearity in the detection range of 62 pg/mL to 1 μg/mL with a detection limit as low as 7.9 pg/mL (S/N = 3). The sensor showed stable recovery and low relative standard deviation in real sample detection. Additionally, the sensor exhibited excellent stability, selectivity, and reproducibility. The reproducibility of the electrodes was evaluated, and the accuracy of the individual electrode current values was calculated to range from 0.5% to 2.71% with an RSD of 1.74%. Such PEC sensor guarantees to supply a brand-new approach to the detection of Pb2+. [Display omitted] • Z-scheme Fe 2 O 3 /g-C 3 N 4 serve as sensing matrix exhibited excellent PEC behavior. • Z-scheme heterojunctioncan inhibit the recombination of e-/h+. • ZnO is used as an aptamer label, which greatly reduces the detection limit. • PEC sensor exhibited a low detection limit of 7.9 pg/mL for Pb2+. [ABSTRACT FROM AUTHOR]

[Display omitted] • Zn-Fe 2 O 3 /CdIn 2 S 4 as sensing platform to provide a stable PEC signal. • Ag@CuWO 4 as an antibody marker, which greatly reduces the detection limit. • PEC sensor exhibited a low detection limit of 14.7 fg/mL for CEA. • Handheld workstation controlled by smartphone for on-site testing of CEA. Carcinoembryonic antigen (CEA) is expressed in many tumor cells and is an important cancer marker in human serum. To assess human health, a rapid and accurate real-time detection method should be established for the sensitive detection of CEA. In this work, real-time and on-site CEA detection was achieved by constructing sandwich-type photoelectrochemical (PEC) immunosensor and using a portable electrochemical workstation controlled by a smartphone. The employment of Zn-doped Fe 2 O 3 /CdIn 2 S 4 (Zn-Fe 2 O 3 /CdIn 2 S 4) is proposed for the first time as a sensing platform for PEC sensor. Due to its suitable band gap combination, a stepped electron transfer pattern provides a stable photocurrent response. Ag@CuWO 4 as an antibody marker can amplify the sensor signal due to its ability to form a Z-type electron transfer mode with CdIn 2 S 4. The Box-Behnken experiment was used to eliminate the interaction of experimental conditions and screen out the optimal experimental conditions for the immunosensor. In addition, the PEC immunosensor has a good linear relationship with CEA in the detection range of 100 fg/mL to 100 ng/mL, with a detection limit as low as 14.7 fg/mL (S/N = 3). The immunosensor has portable characteristics, good stability, reproducibility, specificity, and storage stability. It showed appreciable recoveries and low relative standard deviations in human serum sample analysis. This PEC assay paves a new point-of-care testing method for other cancer markers, particularly environmental contaminants. [ABSTRACT FROM AUTHOR]

Lead ions (Pb2+) are heavy metal ions that are harmful to living organisms and ecosystems. It is important to realize sensitive detection of Pb2+ in the environment. In this study, a signal enhancement photoelectrochemical (PEC) sensor with high sensitivity was constructed for the detection of Pb2+. Firstly, to obtain excellent electron transfer performance, sulfur defect–engineered Bi 2 S 3–x /In 2 S 3–y mediated signal enhancement formed by Bi 2 S 3 and In 2 S 3 with well–matched structure in terms of energy level as the substrate materials. In this case, the introduction of sulfur vacancies further affects the electronic structure of the material, which significantly improves the electrical conductivity and effectively increases the electron transfer rate. In addition, the as–synthesized Cu@Cu 2 O nanosphere is chosen as the marker to accelerate the electron transfer through the surface plasmon resonance effect of Cu. The constructed sensor was able to detect Pb2+ in the range of 1 ng mL−1–100 μg mL−1 with a limit of detection of 19.2 pg mL−1. The sensor exhibits good reproducibility, specificity, and stability, indicating such PEC sensor can achieve the sensitive detection of Pb2+ in the environment. This work paves a new way for the construction of PEC sensors and the specific PEC detection of Pb2+ in environmental waters. [Display omitted] • Bi 2 S 3-x /In 2 S 3-y containing sulfur vacancies as substrate materials. • The introduction of sulfur vacancies promotes electron transfer. • Cu@Cu 2 O nanospheres as labeling and SPR effect of Cu to accelerate electron transfer. • Pb2+ breaks the phosphodiester bond in the aptamer. [ABSTRACT FROM AUTHOR]

Photoelectrochemical (PEC) sensors have attracted much attention due to their low cost, simple instrumentation and high sensitivity. However, conventional PEC sensors require layer–by–layer modification of the photoelectrode surface, which has the disadvantages of being time–consuming and unstable. In addition, complex interfering substances in real samples may lead to false–positive or false–negative detection results. It was thought that the above drawbacks could be eliminated by the construction of a polarity inversion PEC sensor. In this work, a magnetically separated PEC sensor was constructed for the detection of Carcinoembryonic antigen (CEA). During the experiment, the construction of the sensor was used for sensitive detection of CEA. In the experimental process, Fe 3 O 4 @SiO 2 @CdS, a semiconductor material with magnetic properties, was chosen as the substrate material, and ZnO/CuO was used as the marker on the DNA 2 molecule, and a split magnetic separation PEC sensor was constructed, which was used to realize the sensitive detection of CEA. Eventually, the detection range of the sensor for CEA detection is 1–10000 pg/mL, with the detection limit of 0.34 pg/mL. Additionally, the PEC sensor has the advantages of high speed, high efficiency, high sensitivity, good specificity, and high stability. The sensing platform constructed in this work can also be extended to detect other targets, which provides a new idea for PEC sensing platforms. In this experiment, we developed a split PEC immunosensor based on magneto–optic nanostructure and photocurrent polarity switching strategy. Specifically, the proposed magnetic nanostructure Fe 3 O 4 @SiO 2 @CdS–DNA 1 exhibits good paramagnetism and dispersion ability. By magnetic separation process, the PEC signals of opposite polarity can be obtained. [Display omitted] • Fe 3 O 4 @SiO 2 @CdS has good magnetic properties. • The detection limit of CEA was 0.34 pg/mL. • The construction strategy of the sensor is polarity inversion. • ZnO/CuO with excellent photocurrent activity was chosen as the marker. [ABSTRACT FROM AUTHOR]