Search Results (20)

In photoelectrochemical (PEC) biosensing, efficient electron-hole separation is crucial to obtain preferred photocurrent response and analytical performance; thus, constructing developed heterointerfaces with high carrier transfer efficiency is an effective method for sensitive evaluation of analytes. Herein, a 1D ZnIn₂S₄ nanosheet-decorated 2D In₂O₃ tube was developed to integrate with a prostate antigen (PSA)-sensitive aptamer for sensitive PSA antigen detection. 1D In₂O₃ tubes were first prepared by two-step hydrothermal and annealing methods, followed by the in-situ growth of ZnIn₂S₄ nanosheets. Morphology, optical properties, structure, and PEC performance of prepared In₂O₃-ZnIn₂S₄ were characterized by scanning electron microscopy, transmission electron microscopy, ultraviolet–visible spectrophotometry, X-ray diffraction, X-ray photoelectron spectroscopy, and an electrochemical workstation. Benefiting from the photoelectric effect and specific 1D/2D hierarchical structure, In₂O₃-ZnIn₂S₄ displayed enhanced optical absorption and photocarrier separation, thus a superior photoelectrochemical response. Proposed bioassay protocol possessed a linear range from 0.001 to 50 ng/mL and a detection limit at 0.00037 ng/mL. In addition, this biosensor exhibited satisfactory anti-interface ability and stability, which also could be extended to other quantitative platforms for detecting other proteins. Full article

A novel photoelectrochemical (PEC) biosensor was proposed by preparing Au NP/MXene–BiOCl Moiré superlattice nanosheets as the probes. Upon irradiation with visible light, the probe exhibited excellent electrical conductivity as well as high photoelectric conversion efficiency. Benefitting from the excellent PEC property of the hybrid probe, sensitive and accurate detection of protein kinase activity was demonstrated with a limit of detection of 0.0029 U mL⁻¹. This study verifies the great PEC potential of MXene hybrid nanomaterials. Full article

Microelectrode-based photoelectrochemical (PEC) technology is a novel and rapidly developing analytical method for the in vivo probing of neurochemical events in the brain, which is distinguished by its low background noise and high detection sensitivity. This mini-review focuses on recent advances in in vivo PEC biosensors. We classify the key characteristics of PEC technology and elucidate its underlying principles. Furthermore, newly developed PEC neurochemical sensing methods for detecting various substances, including SO₂, antibiotics, metal ions, neurotransmitters, and thioalcohols, as well as cells are discussed. Finally, this review concludes with a comprehensive summary and perspectives on the emerging opportunities and challenges facing this field. Full article

Ascorbic acid plays an important role in the synthesis and metabolism of the human body. However, it cannot be synthesized by the human body and needs to be supplemented from exogenous food intake. Ascorbic acid is easily degraded during storage and heating, often causing its content in food to change. It is important to develop a sensitive and accurate photoelectrochemistry (PEC) biosensor for detecting ascorbic acid. The shortage of PEC materials with long illumination wavelengths and low bias voltages impedes the development of ascorbic acid biosensors. Herein, a 3,4,9,10-perylenetetracarboxylic dianhydride (PDA) self-assembly rod material was firstly reported to show significant photocurrent increases to ascorbic acid at 630 nm illumination and 0 V vs. Ag/AgCl. Moreover, the PDA self-assembly rod material was used as a PEC platform to detect ascorbic acid. This self-powered PEC biosensor exhibited a linear response for ascorbic acid from 5 μM·L⁻¹ to 400 μM·L⁻¹; the limit of detection was calculated to be 4.1 μM·L⁻¹. Compared with other ascorbic acid biosensors, the proposed self-powered PEC biosensor shows a relatively wide linear range. In addition, the proposed self-powered PEC biosensor exhibits good practicability in beverage samples. Full article

Direct detection of miRNA is currently limited by the complex amplification and reverse transcription processes of existing methods, leading to low sensitivity and high operational demands. Herein, we developed a CRISPR/Cas13a-mediated photoelectrochemical (PEC) biosensing platform for direct and sensitive detection of miRNA-21. The direct and specific recognition of target miRNA-21 by crRNA-21 eliminates the need for pre-amplification and reverse transcription of miRNA-21, thereby preventing signal distortion and enhancing the sensitivity and precision of target detection. When crRNA-21 binds to miRNA-21, it activates the trans-cleavage activity of CRISPR/Cas13a, leading to the non-specific cleavage of biotin-modified DNA with uracil bases (biotin-rU-DNA). This cleavage prevents the biotin-rU-DNA from being immobilized on the electrode surface. As a result, streptavidin cannot attach to the electrode via specific biotin binding, reducing spatial resistance and causing a positively correlated increase in the photocurrent response. This Cas-PEC biosensor has good analytical capabilities, linear responses between 10 fM and 10 nM, a minimum detection limit of 9 fM, and an excellent recovery rate in the analysis of real human serum samples. This work presented an innovative solution for detecting other biomarkers in bioanalysis and clinical diagnostics. Full article

Highly sensitive and specific biomarker detection is of outstanding importance for the diagnosis and treatment of cancers. Herein, we developed robust photoelectrochemical (PEC) biosensors with low background noise and high sensitivity based on a heterojunction, which can improve semiconductor photoelectric properties by limiting the recombination of photogenerated electron–hole pairs and successfully widening the range of light absorption. Alpha-fetoprotein (AFP) was used as a target model to examine the analytical performances of the designed PEC biosensors. ZnO/Cs₃MnBr₅ heterogeneous film with a uniform porous structure and large surface area enhanced electron transfer and biomolecule immobilization, and significantly increased the photocurrent response. Under the optimal conditions, the designed PEC biosensor exhibited a linear detection range of 0.01–500 ng/mL and a detection limit of 12 pg/mL. In addition, this PEC biosensor performed well when testing human serum samples and exhibited good repeatability, stability over time, and specificity, showing enormous potential for the detection of cancer markers in future biological and clinical research. Full article

The ratiometric detection method has a strong attraction for photoelectrochemical bioanalysis due to its high reliability and real-time calibration. However, its implementation typically depends on the spatial resolution of equipment and the pairing of wavelength/potential with photoactive materials. In this paper, a novel ratiometric photoelectrochemical biosensor based on front and back illumination was prepared for the detection of glutathione (GSH). Unlike traditional ratio methods, this ratiometric biosensor does not require voltage and wavelength modulation, thereby avoiding potential crosstalk caused by voltage and wavelength modulation. Additionally, the formation of a heterojunction between mTiO₂ and Ag₂S is conducive to enhancing light absorption and promoting charge separation, thereby boosting the photocurrent signal. Apart from forming a heterojunction with TiO₂, Ag₂S also shows a specific affinity towards GSH, thus enhancing the selectivity of the mTiO₂/Ag₂S ratiometric photoelectrochemical biosensor. The results demonstrate that the ratiometric photoelectrochemical biosensor exhibits a good detection range and a low detection limit for GSH, while also possessing significant interference elimination capability. The GSH detection range is 0.01–10 mmol L⁻¹ with a detection limit of 6.39 × 10⁻³ mmol·L⁻¹. The relative standard deviation of 20 repeated detections is 0.664%. Impressively, the proposed novel ratiometric PEC biosensor demonstrates enviable universality, providing new insights for the design and construction of PEC ratiometric sensing platforms. Full article

It is highly attractive to develop a photoelectrochemical (PEC) sensing platform based on a non-noble-metal nano array architecture. In this paper, a PEC hydrogen peroxide (H₂O₂) biosensor based on Ni/WS₂/WC heterostructures was synthesized by a facile hydrothermal synthesis method and melamine carbonization process. The morphology, structural and composition and light absorption properties of the Ni/WS₂/WC catalyst were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV–visible spectrophotometer. The average size of the Ni/WS₂/WC nanosheets was about 200 nm. Additionally, the electrochemical properties toward H₂O₂ were studied using an electrochemical workstation. Benefiting from the Ni and C atoms, the optimized Ni/WS₂/WC catalyst showed superior H₂O₂ sensing performance and a large photocurrent response. It was found that the detection sensitivity of the Ni/WS₂/WC catalyst was 25.7 μA/cm²/mM, and the detection limit was 0.3 mmol/L in the linear range of 1−10 mM. Simultaneously, the synthesized Ni/WS₂/WC electrode displayed excellent electrocatalytic properties in hydrogen evolution reaction (HER), with a relatively small overpotential of 126 mV at 10 mA/cm² in 0.5 M H₂SO₄. This novel Ni/WS₂/WC electrode may provide new insights into preparing other efficient hybrid photoelectrodes for PEC applications. Full article

Graphene and graphene-like two-dimensional layered nanomaterials-based photoelectrochemical (PEC) biosensors have recently grown rapidly in popularity thanks to their advantages of high sensitivity and low background signal, which have attracted tremendous attention in ultrahigh sensitive small molecule detection. This work proposes a non-enzymatic and visible-light-sensitive PEC biosensing platform based on ZIF-67@MoS₂/rGO composite which is synthesized through a facile and one-step microwave-assisted hydrothermal method. The combination of MoS₂ and rGO could construct van der Waals heterostructures, which not only act as visible-light-active nanomaterials, but facilitate charge carriers transfer between the photoelectrode and glassy carbon electrode (GCE). ZIF-67 anchored on MoS₂/rGO heterostructures provides large specific surface areas and a high proportion of catalytic sites, which cooperate with MoS₂ nanosheets, realizing rapid and efficient enzyme-free electrocatalytic oxidation of glucose. The ZIF-67@MoS₂/rGO-modified GCE can realize the rapid and sensitive detection of glucose at low detection voltage, which exhibits a high sensitivity of 12.62 μAmM⁻¹cm⁻². Finally, the ZIF-67@MoS₂/rGO PEC biosensor is developed by integrating the ZIF-67@MoS₂/rGO with a screen-printed electrode (SPE), which exhibits a high sensitivity of 3.479 μAmM⁻¹cm⁻² and a low detection limit of 1.39 μM. The biosensor’s selectivity, stability, and repeatability are systematically investigated, and its practicability is evaluated by detecting clinical serum samples. Full article

A photoelectrochemical (PEC) detection platform was built based on the branched rutile/anatase titanium dioxide (RA-TiO₂) electrode. Theoretical calculations proved that the type-II band alignment of rutile and anatase could facilitate charge separation in the electrode. The self-generated electric field at the interface of two phases can enhance the electron transfer efficiency of the electrode. Carboxylated CdTe quantum dots (QDs) were applied as signal amplification factors. Without the target DNA presence, the CdTe QDs were riveted to the surface of the electrode by the hairpin probe DNA. The sensitization of CdTe QDs increased the photocurrent of the electrode significantly. When the target DNA was present, the structural changes of the hairpin probe DNA resulted in the failure of the sensitized structure. Benefiting from excellent electrode structure design and CdTe QDs sensitization strategy, the PEC assays could achieve highly sensitive and specific detection of target DNA in the range of 1 fM to 1 nM, with a detection limit of 0.23 fM. The electrode construction method proposed in this article can open a new avenue for the preparation of more efficient PEC sensing devices. Full article

The formation of heterojunction structures can effectively prevent the recombination of photogenerated electron–hole pairs in semiconductors and result in the enhancement of photoelectric properties. Using TiO₂ nanotubes (prepared using the hydrothermal-impregnation method) as carriers, CdS-TiO₂NTs were fabricated as a photoelectrochemical (PEC) sensor, which can be used under visible light and can exhibit good PEC performance due to the existence of the heterojunction structure. The experimental results show that the prepared CdS-TiO₂NTs electrode had a linear response to 2–16 mM glutathione (GSH). The sensor’s sensitivity and detection limit (LOD) were 102.9 µA·mM⁻¹ cm⁻² and 27.7 µM, respectively. Moreover, the biosensor had good stability, indicating the potential application of this kind of heterojunction PEC biosensor. Full article

The electrodes of two-dimensional (2D) titanium dioxide (TiO₂) nanosheet arrays were successfully fabricated for microRNA-155 detection. The (001) highly active crystal face was exposed to catalyze signaling molecules ascorbic acid (AA). Zero-dimensional (0D) titanium carbide quantum dots (Ti₃C₂T_x QDs) were modified to the electrode as co-catalysts and reduced the recombination rate of the charge carriers. Spectroscopic methods were used to determine the band structure of TiO₂ and Ti₃C₂T_x QDs, showing that a type Ⅱ heterojunction was built between TiO₂ and Ti₃C₂T_x QDs. Benefiting the advantages of materials, the sensing platform achieved excellent detection performance with a wide liner range, from 0.1 pM to 10 nM, and a low limit of detection of 25 fM (S/N = 3). Full article

Designable and ultrathin covalent organic framework nanosheets (CONs) with good photoelectric activity are promising candidates for the construction of photoelectrochemical (PEC) biosensors for the detection of low-abundance biological substrates. However, achieving highly sensitive PEC properties by using emerging covalent organic framework nanosheets (CONs) remains a great challenge due to the polymeric nature and poor photoelectric activity of CONs. Herein, we report for the first time the preparation of novel composites and their PEC sensing properties by electrostatic self-assembly of ultrathin CONs (called TTPA-CONs) with Ti₃C₂T_x. The prepared TTPA-CONs/Ti₃C₂T_x composites can be used as photocathodes for PEC detection of prostate-specific antigen (PSA) with high sensitivity, low detection limit, and good stability. This work not only expands the application of CONs but also opens new avenues for the development of efficient PEC sensing platforms. Full article

Based on the enhanced charge separation efficiency of the one-dimensional structure and strong surface plasmon resonance (SPR) of gold, a gold modified TiO₂ nanotube (Au/TiO₂NTs) glucose photoelectrochemical (PEC) sensor was prepared. It could be activated by visible red light (625 nm). Under optimal conditions, the Au/TiO₂NTs sensor exhibited a good sensitivity of 170.37 μA·mM⁻¹·cm⁻² in the range of 1–90 μM (R² = 0.9993), and a detection limit of 1.3 μM (S/N = 3). Due to its high selectivity, good anti-interference ability, and long-term stability, the fabricated Au/TiO₂NTs sensor provides practical detection of glucose. It is expected to be used in the construction of non-invasive PEC biosensors. Full article

Nowadays, the emerging photoelectrochemical (PEC) bioanalysis has drawn intensive interest due to its numerous merits. As one of its core elements, functional nanostructured materials play a crucial role during the construction of PEC biosensors, which can not only be employed as transducers but also act as signal probes. Although both chemical composition and morphology control of nanostructured materials contribute to the excellent analytical performance of PEC bioassay, surveys addressing nanostructures with different dimensionality have rarely been reported. In this review, according to classification based on dimensionality, zero-dimensional, one-dimensional, two-dimensional, and three-dimensional nanostructures used in PEC bioanalysis are evaluated, with an emphasis on the effect of morphology on the detection performances. Furthermore, using the illustration of recent works, related novel PEC biosensing patterns with promising applications are also discussed. Finally, the current challenges and some future perspectives in this field are addressed based on our opinions. Full article