Search

Low‐gate voltages can make large modulations in the drain current. Accordingly, organic electrochemical transistors (OECTs) have attracted considerable interest as amplifying transducers. The use of OECTs in combination with electrochemical analysis promises to promote sensing performance. Herein, an OECT‐based photoelectrochemical‐type (OECT‐PEC) sensor is constructed based on the photo‐induced potential generating variation in the drain current. The as‐constructed OECT‐PEC sensor has high sensitivity because the device incorporated a sensor and an amplifier, providing the benefits of a PEC sensor and an OECT. In addition to the advantages of excellent signal amplification and ease of miniaturization, background signals are also effectively reduced, and possible interferences from electroactive substances are avoided due to the separation of light excitation and the electric output. The OECT‐PEC sensor integrates poly(3,4‐ethylenedioxythiophene) (PEDOT)‐modulated Fe‐metal organic framework (Fe‐MOF) nanocomposites as the photo‐active gating material and poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the channel material which exhibits a good photocurrent response from the gate electrode and a corresponding 100‐fold expansion channel response. With aptamer as the recognition element, a sensitive OECT‐PEC biosensor is constructed to detect the organophosphorus pesticide malathion. It is found to exhibit a good linear range, a low detection limit, and better sensitivity than the traditional PEC method. [ABSTRACT FROM AUTHOR]

The 3,3′,5,5′-tetramethylbenzidine-H 2 O 2 (TMB-H 2 O 2) platform has gained widespread use for rapid detection of various analytes in foods. However, the existing TMB-H 2 O 2 platforms suffer from limited accuracy, as their signal output is confined to the visible region, which is prone to interference from various food colorants in real samples. To address this challenge, a novel Au@Os-mediated TMB-H 2 O 2 platform is developed for both rapid and accurate detection of analytes in foods. The prepared Au@Os NPs exhibit remarkable peroxidase-like activity, making the platform display dual absorption peaks in visible and near-infrared (NIR) regions, respectively. This Au@Os-mediated TMB-H 2 O 2 platform exhibited three linear ranges across different concentrations of ziram from 1–100, 150–600, and 800–2000 nM with limit of detection (LOD) 7.9 nM and limit of quantification (LOQ) 24.15 nM respectively. Further, the Au@Os-mediated TMB-H 2 O 2 platform was also used for rapid and accurate detection of ziram in real food samples like apple, tomato, and black tea. • Synthesis of a novel Au@Os core-shell NPs with excellent peroxidase-like activity. • Au@Os mediated TMB-H 2 O 2 sensing platform with Vis and NIR absorption signal-output. • Rapid and accurate detection of ziram in real foods. • Improved sensitivity for ziram detection with LOD of 7.9 nM and LOQ of 24.15 nM. [ABSTRACT FROM AUTHOR]

Although the use of omethoate (OMT) for pests control is enormously economically beneficial for agricultural production, the high toxicity of OMT to nontarget organisms has resulted in the contamination of soil, river water, and food materials. Developing sensitive and convenient techniques to detect OMT residues is vital to society. Electrochemiluminescence (ECL) is a powerful analytical tool and has been widely applied in biosensors. To boost the co-reaction efficiency and ECL intensity, we introduced defective ZIF-8 as the novel cathodic luminophore. At the same time, defect generated by the doping of MoTe 2 nanoparticles into ZIF-8 could easily electrocatalytic reduce the co-reactor S 2 O 8 2− to SO 4 •- . Hence, based on the catalysis of defective ZIF-8, the ECL intensity of MoTe 2 /ZIF-8 nanocomposites is much higher than both ZIF-8 and MoTe 2 nanoparticles. By integration of as-prepared materials with specificity omethoate aptamer, the ECL sensor showed a broad linear range (10−10 g L−1 and 10−5 g L−1) and a comparatively low detection limit (3.3 × 10−11 g L−1). Besides, the ECL aptasensor appeared a good practical performance to detect potato and spinach extraction samples, which proposed a promising guideline for developing ECL aptasensors with high efficiency. •Defective ZIF-8 was induced by nanoparticle-doping via 'de novo' strategy. • The as-prepared defective ZIF-8 was employed as novel cathodic ECL luminophore. • High electrocatalytic active ZIF-8 significantly boosted co-reaction efficiency. • A high-performance ECL omethoate aptasensor was successfully established. • The ECL aptasensor exhibited good selectivity and sensitivity. [ABSTRACT FROM AUTHOR]

• MoTe 2 NPs/RGO based on Schottky barriers was synthesized by one-step synthesis. • The photocurrent was enhanced due to lower recombination of electrons and holes. • MoTe 2 NPs/RGO adopted as photoactive material the first time was applied in PEC. • A visible light-driven PEC profenofos aptasensor was successfully established. • The PEC aptasensor exhibited excellent selectivity and sensitivity for profenofos. Schottky barrier with a suitable barrier height which acts as the electron tank can reduce the recombination of photogenerated electronic-hole pairs, consequently leads to higher photoelectric properties. Telluride molybdenum nanoparticles (MoTe 2 NPs) are a kind of transition-metal dichalcogenides, which is a burgeoning class of materials with low toxicity, high specific surface area, high carrier mobility, and wide spectral absorption. In order to enhance the photoelectric performance of MoTe 2 , we adopted a one-step hydrothermal synthesis to construct MoTe 2 NPs/reduced graphene oxide (RGO) heterostructures with suitable Schottky barrier. The photocurrent intensity of MoTe 2 NPs/RGO heterostructures was 21.8 times of RGO and 10.5 times of MoTe 2 NPs. On the basis of excellent visible light-responsive of MoTe 2 nanoparticles/RGO, a label-free PEC aptasensor for the detection of profenofos (PRO) was successfully constructed, indicating that MoTe 2 nanoparticles/RGO would be a promising visible light-responsive photoactive material for PEC biosensors. This aptasensor exhibited a wide linear range (10−9 g L–1 and 10−2 g L–1) and a relatively low detection limit (3.3 × 10−10 g L−1). At the same time, the application of Schottky barrier in the field of photoelectric sensing was expanded. [ABSTRACT FROM AUTHOR]

Synopsis: Diagram of one-step synthesis of core-shell LaFeO 3 @g-C 3 N 4 heterostructure and photoelectrochemical and optical absorption properties of various materials. • The LaFeO 3 @g-C 3 N 4 heterostructure was synthesized by facile one-step method. • The LaFeO 3 @g-C 3 N 4 showed superior PEC properties than LaFeO 3 /g-C 3 N 4. • A PEC aptasensor was constructed for detection of streptomycin. • The proposed aptasensor has a wide linear range and low detection limits. The development of core-shell heterostructure photoactive materials with high visible light response and charge separation efficiency is of great significance. Herein, we prepared LaFeO 3 @g-C 3 N 4 p-n heterojunction with core-shell structure by using facile one-step method. As a contrast, g-C 3 N 4 nanosheets decorated with LaFeO 3 nanoparticles (LaFeO 3 /g-C 3 N 4) were synthesized by a reported method. The LaFeO 3 @g-C 3 N 4 heterostructure boosted the visible light response and effectively separated charge carriers compared to LaFeO 3 /g-C 3 N 4. Moreover, for LaFeO 3 @g-C 3 N 4 heterostructure, the interaction of core-shell interface and synergistic effect of p-n heterojunction made photoelectrochemical (PEC) properties more stable and excellent. Concretely, the absorption band edge of LaFeO 3 @g-C 3 N 4 heterostructure was about 700 nm, which was wider than LaFeO 3 /g-C 3 N 4. Additionally, the photocurrent signal of LaFeO 3 @g-C 3 N 4 heterostructure was 2.3-fold higher than that of LaFeO 3 /g-C 3 N 4. Thus, on the basis of the prominent PEC performance of LaFeO 3 @g-C 3 N 4 heterostructure, we constructed a PEC aptasensor to detect streptomycin (STR) sensitively and selectively. The aptasensor revealed a wide linear concentration range from 0.01 nM to 10000 nM of STR, with a low detection limit of 0.0033 nM (S/N = 3). The fabricated aptasensor had excellent stability, practicability, and reproducibility, laying a good foundation for STR detection in other analytical fields. [ABSTRACT FROM AUTHOR]

Developing a simple, rapid detection method for the analysis of edifenphos (EDI) is crucial due to its residue is harmful to acetylcholinesterase on the human cellular system, and cause a lot of complications. Herein, we synthesized visible light-responsive MoS 2 nanosheets decorated with Zinc phthalocyanine (ZnPc) nanoparticles (ZnPc/n-MoS 2). Due to the sensitization of ZnPc nanoparticles, the resulting ZnPc/n-MoS 2 exhibited narrower energy bandgap and efficient charge transfer. Especially, the carrier lifetime of ZnPc/n-MoS 2 is 2 more times longer than n-MoS 2 , and the photocurrent intensity of ZnPc/n-MoS 2 is 24 times of n-MoS 2 and 22 times of ZnPc nanoparticles under visible light irradiation. Further, a visible light-responsive ultrasensitive photoelectrochemical (PEC) aptasensor for selectivity recognition of EDI was triumphantly established by using EDI aptamer as a biorecognition element, which exhibited a wide linear ranking from 5 ng L–1 to 10 μg L–1 (R2 = 0.996) and a low detection limit of 1.667 ng L–1 (S/N = 3). The splendid performance of the ZnPc/n-MoS 2 nanosheet ultrasensitive sensing platform can be applied to detect the concentration of EDI in food, biomedical and environmental analysis. • Visible light-responsive ZnPc/n-MoS 2 was fabricated used ZnPc nanoparticles as sensitizer. • The carrier lifetime and photocurrent intensity of ZnPc/n-MoS 2 is 2 more and 24 times of n-MoS 2 , respectively. • A visible light-driven PEC edifenphos aptasensor was firstly successfully established. • The proposed aptasensor exhibited good selectivity and sensitivity for edifenphos detection. [ABSTRACT FROM AUTHOR]

The detection of transmissible gastroenteritis virus (TGEV) is of great significance to reduce the loss of pig industry. A LAMP-visualization/PFC self-powered dual-mode output sensor platform was constructed to detect TGEV by combining a simple and intuitive photoelectrochromic material with a highly sensitive PFC self-powered sensing platform without external power supply. The PFC sensing substrate was constructed using CdS nanoparticles modified ZnO NRs (CdS/ZnO NRs) as the photoanode, which exhibited high photoactivity, and Prussian blue (PB) as the cathode. After LAMP reaction on the optical anode, visual signals caused by PB discolorimetry can be detected semi-quantitatively, or PFC power density electrical signals collected by electrochemical workstation can be used. The output power density value is logarithm of TGEV concentration. The linear relationship was good within the detection range of 0.075 fg/μL-7.5 ng/μL, with a detection limit of 0.025 fg/μL (S/N = 3). This multi-signal output sensing platform provides more choices for quantifying TGEV detection results, and the two methods can be mutually verified, which meets the needs of different scenarios and improves the reliability of detection. It has a good effect in the actual sample detection, without the use of expensive and complex instruments, and has a broad application prospect. [Display omitted] • Dual-mode output sensor platform for TGEV detection was constructed. • Combination of visualization/PFC self-powered sensors and nucleic acid amplification. • Simple and intuitive visual color change without external power supply. • The chip with detection limit of 0.025 fg/μL, good selectivity and stability. [ABSTRACT FROM AUTHOR]

Synopsis: Successful preparation of VOPc/CN photoactive materials and construction of PEC aptasensor for DCF detection. • Facile method with easy fabrication enabled the visible/NIR light response PEC sensor for rapid DCF detection. • VOPc/CN nanocomposites was first used as photoactive materials. • VOPc/CN based on VOPc sensitizing CN extend spectral range to visible/ NIR light region. • VOPc/CN photoactive materials demonstrated improved photoelectric conversion efficiency. • This biosensor showed a good sensitivity and a wide linear range. A novel photoelectrochemical (PEC) aptasensor for diclofenac detection, based on visible/near-infrared (vis/NIR) light-responsive vanadyl-phthalocyanine/graphitic carbon nitrid nanosheet (VOPc/CN) nanocomposites, was successfully fabricated. In this work, the first coupling of CN and VOPc with a facile solution–phase method was prepared and applied to PEC sensing. The UV–vis diff ;use reflection spectra (DRS) indicated that VOPc is an excellent photosensitizer when applied to the surface of CN. It promoted CN light absorption to the visible-NIR region, which greatly enhanced the light excitation capability. The PEC signal of the VOPc/CN nanocomposites improved 2.7 and 12.42-fold compared with pure VOPc and CN, respectively, indicating that VOPc/CN nanocomposites have good photoelectric activity and enhanced photo-to-current conversion efficiency. As a result, VOPc sensitized CN was introduced as a covalent immobilizing PEC aptasensor for the sensitive and selective determination of diclofenac (DCF). Under optimal conditions, the fabricated PEC biosensor exhibited good PEC performances with high sensitivity, a low detection limit of 0.03 nM (S/N = 3) and a wide linear response, in the range of 0.1-500 nM. This was due to the specific interaction between DCF and the aptamer. It is concluded that VOPc/CN nanocomposites are potentially promising photoactive materials for applications in PEC biosensors, as well as for photocatalysis and other related fields. [ABSTRACT FROM AUTHOR]

Oxygen defect-engineered is an important strategy to improve the photoelectric activity of materials. Herein, a facile one-pot solvothermal method was utilized to synthesize visible light-responsive photoactive Bi 2 MoO 6 nanoparticles anchored boron and nitrogen co-doped graphene (BNG) nanosheets nanocomposites with oxygen vacancy. The incorporation of BNG nanosheets increased the oxygen vacancies amounts on Bi 2 MoO 6 remarkably, and the presences of oxygen vacancies can be beneficial to broaden the absorption range. The absorption edge of Bi 2 MoO 6 /BNG was widened from 500 nm to 550 nm compared to Bi 2 MoO 6 , and the charge transfer was accelerated to improve the photoactive of Bi 2 MoO 6 /BNG. Under visible light illumination, the photoelectrochemical (PEC) response of the as-prepared Bi 2 MoO 6 /BNG was 11.6-fold, 6.7-fold, 3.1-fold and 2.4-fold higher than that of pristine Bi 2 MoO 6 , Bi 2 MoO 6 /graphene, Bi 2 MoO 6 /nitrogen doped graphene and Bi 2 MoO 6 /boron doped graphene. Using Bi 2 MoO 6 /BNG nanocomposites with the superior PEC performance as photoactive materials in combination with specifically recognized lincomycin (LIN) aptamer, a highly efficient PEC aptasensor was successfully constructed for sensitive analysis of LIN. Under optimal conditions, the proposed PEC aptasensor exhibited excellent analytical performance for LIN with a wide linear response of 1 × 10−11 to 1 × 10−6 mol L−1 along with a low detection limit of 3.7 × 10−12 mol L−1 (defined as S / N = 3). The as-prepared Bi 2 MoO 6 /BNG nanocomposites exhibit excellent visible light response and PEC performance, indicating its potential applications in PEC biosensor. • Oxygen vacancy engineered Bi 2 MoO 6 /BNG was prepared by one-pot for the first time. • The photocurrent of Bi 2 MoO 6 /BNG was greatly enhanced compared with pristine Bi 2 MoO 6 , Bi 2 MoO 6 /G, Bi 2 MoO 6 /NG and Bi 2 MoO 6 /BG. • A highly efficient PEC lincomycin aptasensor was successfully established. • The proposed aptasensor exhibited excellent superior analytical performance for lincomycin detection. [ABSTRACT FROM AUTHOR]