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Gold nanoparticle (AuNP)–anchored BP nanosheets were synthesized through in situ growth of AuNPs onto BP. Due to the strong chelating ability of P or phosphorus oxides with AuNPs, the stability of BP is improved. As proof-of-concept demonstration of the functionalized BP, electrochemical detection of circulating tumor cells (CTCs) based on BP@AuNPs@aptamer as a probe combined with immunomagnetic separation is reported. The aptamer can specifically bind with CTCs, while the phosphorus oxides including phosphite ion and phosphate ion (PxOy species) on BP and aptamer can react with molybdate to generate an electrochemical current, leading to dual signal amplification. The biosensor is applied to MCF-7 cell detection and displays good analytical performance with a detection limit of 2 cell mL −1 . Furthermore, the practicality of this biosensor was validated through sensitive determination of MCF-7 cells in human blood. Therefore, the reported biosensor could be applied to detect other biomarkers, offering an ultrasensitive strategy for clinical diagnostics. Graphical abstract Electrochemical detection of circulating tumor cells based on gold nanoparticle–modified black phosphorus nanosheets is reported.

In this work, we developed a photoelectrochemical assay for circulating tumor cells (CTCs) detection based on hexagonal carbon-nitrogen tubes (HCNT) as visible light-sensitive materials. The MCF-7 cell was selected as the model CTC and was captured through specific recognition between epithelial cell adhesion molecules (EpCAM) on the cell surface and anti-EpCAM antibodies. Anti-EpCAM antibody-modified magnetic nanoparticles were used to enrich and separate MCF-7 cells from samples. The detection signal was amplified by Ag2S nanocrystals, which can compete with HCNTs for absorbing visible light, leading to a decrease of photocurrent intensity. The linear range of the assay for MCF-7 cells is from 10 to 5000 cells mL−1, with a detection limit of 3 cells mL−1 (S/D = 3). The assay has good selectivity for MCF-7 detection over HeLa cells. The assay was successfully applied for the detection of MCF-7 in human whole blood, which indicates the potential for clinical application.

A “signal-on” photoelectrochemical (PEC) immunosensor was successfully constructed for determination of human epidermal growth factor receptor 2 (HER2) based on organic–inorganic heterojunction Y6/CdS as photoactive material. Compared with single organic semiconductor, Y6, Y6/CdS exhibited higher photoelectric conversion efficiency due to the formation of heterojunction. In the presence of HER2, sandwich immune structure was formed between HER2 aptamer and anti-HER2 antibody (Ab) by specific recognition. The polydopamine (PDA) nanoparticles were used for signal amplification to enhance photocurrent intensity as PDA can act as electron donor to eliminate holes and promote electron–hole pairs separation. The developed PEC sensor displayed a wide detection range of 5–1000 pg mL −1 and a low detection limit of 2.2 pg mL −1 for HER2 (S/N = 3). The sensor was successfully used for the detection of HER2 in serum with recoveries between 94.8 and 104% and relative standard deviations (RSDs) in the range of 1.2–4.3%. Furthermore, the designed immunosensor possessed good stability, selectivity, and reproducibility, which can find potential clinical applications for disease diagnosis. Graphical abstract A “signal-on” photoelectrochemical sensor was reported for human epidermal growth factor receptor 2 detection based on Y6/CdS organic–inorganic heterojunction

A ratiometric fluorescence assay was designed for determination of dipicolinic acid (DPA), a spore-specific compound which is used as a biomarker for Bacillus anthracis spores for food and medical product safety analysis. The dual-channel fluorescence probe integrates two fluorescent materials, Eu 3+ ion and gold nanocluster (Au NC). The Au NC is used as a reference channel to measure background noise and the Eu 3+ ion as the DPA-specific response signal channel. The probe was prepared through simply combing bovine serum albumin (BSA)-scaffolded Eu 3+ ion and Au NCs. When excited at 530 nm, in the presence of DPA, the fluorescence signals of Eu 3+ ion at 595, 617, and 695 nm increased significantly while the 650 nm signal of Au NC reference remained relatively constant. This fluorescence probe has good photo-stability and also displays good selectivity and high sensitivity for DPA with a low detection limit of 0.8 μM. The linear range of the ratiometric probe for DPA is 1–50 μM. For determination of DPA released during the germination of Bacillus subtilis spores, the detection results were in agreement with measurements by conventional calorimetry assay. The method may have potential for measuring the level of contamination and germination by spores. Graphical Abstract Dual-channel fluorescence biosensor was designed to detect dipicolinic acid, a spore-specific compound which is used as a biomarker for Bacillus anthracis spores for food and medical product safety analysis

A sensitive photoelectrochemical (PEC) sensor based on hexagonal carbon nitride tubes (HCNT) as photoactive material was prepared for the detection of human epidermal growth factor receptor 2 (HER2). Magnetic Fe3O4 nanospheres (MNs) modified with anti-HER2 antibodies were employed for highly efficient capture of HER2 from serum sample, and Co3O4 nanoparticles (Co3O4 NPs) modified with ascorbic acid oxidase (AAO) as well as HER2 aptamer were used for signal amplification. When the aptamer-Co3O4-AAO probe was captured onto the electrode surface through the specific binding of the aptamer with HER2, the photocurrent intensity decreased. This was because Co3O4 NPs competed with HCNT for consumption of the excitation energy. As a consequence AAO catalyzed the oxidation of the electron donor (AA), and the aptamer-Co3O4-AAO probe increased the steric hindrance at the electrode surface, leading to significant photocurrent intensity decrease, thus realizing multiple signal amplification. Based on this signal amplification strategy, at 0 V (vs Ag/AgCl), the PEC sensor shows a wide linear response ranging from 1 pg mL−1 to 1 ng mL−1 with a low detection limit of 0.026 pg mL−1 for HER2. Importantly, the prepared PEC sensor was applied for detection of HER2 in human serum samples with recoveries between 98.8 and 101%.

Intelligent prediction, accurate diagnosis, and efficient repair of mechanical equipment faults are critical for ensuring production safety and enhancing efficiency in industrial processes. However, data scarcity and recognition efficiency remain significant challenges in named entity recognition (NER) for mechanical equipment faults. To address these issues, this study proposes a novel NER method based on template-free prompt learning. The model is initialized with limited labeled data and then leverages hidden entity cues in unlabeled data to generate insightful hints, guiding the model through deep retraining. Experimental results demonstrate significant improvements in F1 scores: 29.54%, 22.34%, and 19.67% on the MEFD, CONLL03, and MIT-Movie datasets, respectively, as labeled samples increased from 5 shots to 50 shots. Furthermore, compared to template-based prompt learning methods, the proposed approach achieved F1 score improvements of 9.89%, 12.97%, 9.51%, and 2.21% as labeled samples scaled from 5 shots to 50 shots. The proposed method effectively mitigates data dependency issues, enhances model generalization and application capabilities, and provides robust technical support for the intelligent identification and diagnosis of mechanical equipment faults.

Prussian Blue nanoparticles were deposited on g-C 3 N 4 nanosheets. The resulting nanocomposite possesses peroxidase-like (POx) activity and can catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine at room temperature in the presence of H 2 O 2 . This leads to formation of a blue product with an absorption maximum at 650 nm. The formation of the Prussian Blue nanoparticles on the g-C 3 N 4 nanosheets, and the POx-like activity of the composite were characterized in detail. The POx mimic was used for determination of L-lactic acid via detection of H 2 O 2 that is produced by the enzyme lactate oxidase (LOx). The assay has a linear range that extends from 5 to 100 μM, and the detection limit is 2.2 μM. The method was successfully applied to the determination of L-lactic acid in spiked human serum. Graphical abstract Ultra-small Prussian Blue (PB) nanoparticles were used to modify g-C 3 N 4 nanosheets, and their peroxidase-like activity was explored for detection of L-lactic acid. LOx represent L-lactate oxidase, and TMB represents 3,3′,5,5′-tetramethylbenzidine.

In this work, an aptamer-based photoelectrochemical (PEC) assay is reported for the determination of MCF-7 breast cancer cells using hexagonal carbon nitride tubes (HCNTs) as photoactive material. The aptamer immobilized on the HCNT surface can specifically bind with mucin 1 protein (MUC1) that is overexpressed on the surface of MCF-7 cell. Thus, the PEC assay has high specificity for the determination of MCF-7. The determination of MCF-7 is due to the binding of MCF-7 onto HCNT that suppressed the photocurrent intensity. The PEC assay displays good performances for MCF-7 determination with a linear range from 1 × 10 2 to 1 × 10 5 cell mL −1 and limit of detection down to 17 cells mL −1 . Meanwhile, the PEC assay can distinguish MCF-7 from normal cells in blood samples, which may have potential applications in cancer diagnostics and therapeutics.

Ferroptosis is an iron−dependent form of regulated cell death. It has attracted more and more research interests since it was found because of its potential physiological and pathological roles. In recent years, many efforts have been made for the developments and applications of selective fluorescence probes for real−time and in situ tracking of bioactive species during ferroptosis process, which is necessary and significant to further study the modulation mechanisms and pathological functions of ferroptosis. In this review, we will focus on summarizing the newly developed fluorescence probes that have been applied for ferroptosis imaging in the recent years, and comprehensively discussing their design strategies, including the probes for iron, reactive oxygen species, biothiols and intracellular microenvironmental factors.

Heated tobacco products (HTPs) are a recent category of tobacco products, with their relative safety compared to cigarette smoking and potential to help smokers to quit being two reasons why regulators may consider their market approval. Designed to heat tobacco rather than to burn in order to produce aerosol, different heating techniques are applied to commercial HTPs, which may result in differing aerosol formation. Therefore, each product requires separate assessment. This work focuses on a closed-end HTP (coded as HTP-A), which is electrically heated and designed to allow puffing air flow to bypass its tobacco section, resulting in reduced oxygen concentration within the tobacco section during heating and aerosol forming. To provide a preliminary aerosol chemistry and toxicological screening, this study assessed HTP-A against a commercial electrically heated HTP (IQOS , coded as HTP-B) and a 3R4F reference cigarette. Under Health Canada Intense (HCI) smoking regime, the levels of 9 regulatory priority toxicants in the aerosol of HTP-A were either reduced or comparable to those in HTP-B on a per-stick basis. Additionally, both HTPs showed significant reduction (greater than 90%) in comparison to those measured in mainstream smoke of 3R4F cigarette for these toxicants. Using a set of standard toxicological assays (Ames, Micronucleus and Neutral Red Uptake), the two HTPs showed no observable responses while significant toxicity responses were recorded for 3R4F’s total particulate matter. Based on these preliminary results, the novel closed-end HTP-A design may provide similar toxicological profiles to the comparator HTP-B. Further toxicological and clinical assessments are warranted to evaluate HTP-A’s potential for exposure or disease risk reduction. [Contrib. Tob. Nicotine Res. 32 (2023) 146–156]