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The global surge of mpox virus (MPXV) demands diagnostic tools that combine laboratory-grade accuracy with point-of-care simplicity. Here, we report an all-in-one lateral flow immunoassay (LFIA) leveraging precision-engineered Fe₃O₄-Au_shell heterodimers for dual-signal MPXV quantification via naked-eye readout and photothermal amplification. These monodisperse plasmonic-magnetic nanoparticles, synthesized through controlled seed-mediated heterodimerization, integrate magnetic enrichment, photothermal conversion, and tunable plasmonic resonance into a single architecture. The Fe₃O₄ core enables rapid magnetic separation, while the Au shell provides dual-mode LSPR colorimetry and NIR photothermal quantification. Magnetic separation eliminates preprocessing for direct analysis of untreated samples (e.g., blood, saliva), while photothermal amplification achieves 0.04 ng/mL sensitivity (125 × lower than visual detection). Dual-signal cross-verification ensures reliability: a 5 ng/mL naked-eye threshold supports rapid screening, complemented by photothermal linear quantification (1-1000 ng/mL, R² = 0.992) for precise viral load assessment. Validated with 100 % specificity against influenza and 93.3-98.5 % recovery in serum samples, this platform shows promising potential in point-of-care pathogens detection in resource-limited area.

Enzymatic biofuel cell-based self-powered sensors represent a promising class of portable sensing devices, so the development of a novel and efficient self-powered sensing strategy is of critical importance. Herein, the direct electron transfer (DET) of bilirubin oxidase (BOD) is modulated through enzymatic reaction-triggered DNA structure transformation, which is further applied for self-powered detection of T4 polynucleotide kinase (T4 PNK) activity. The biocathode of a glucose/oxygen biofuel cell is prepared by immobilizing BOD on carbon nanotubes (MWCNTs)-gold nanoparticles (AuNPs) nanocomposite by using a short-stranded DNA (sDNA)-complementary DNA (cDNA) duplex as a bridge. For detecting T4 PNK activity, the biocathode is incubated with T4 PNK and adenosine triphosphate to phosphorylate the 5'-hydroxyl termini of sDNA, followed by λ-exonuclease digestion of the phosphorylated sDNA, resulting in structure transformation of cDNA into a hairpin configuration via intramolecular base-pairing. As a result, BOD is repositioned near the MWCNTs-AuNPs interface, permitting efficient oxygen reduction catalysis through the DET. Consequently, the glucose/oxygen biofuel cell switches from an initial "open-circuit" to a "closed-circuit" operational mode, enabling self-powered detection of T4 PNK activity. The linear range for T4 PNK activity detection is from 0.001 to 2 U mL^-1, with a low detection limit of 3 × 10^-4 U mL^-1. The self-powered sensor is successfully used for detcting T4 PNK activity in a human serum sample. This work presents a novel strategy for self-powered sensing by modulating the DET of BOD via enzymatic reaction-triggered DNA structure transformation.

Dried blood spots (DBS) offer a practical and relatively non-invasive method for sample collection. Here, we evaluate the feasibility of applying ¹H NMR spectroscopy to metabolomic analysis of DBS. Various solvent suppression techniques and extraction protocols were tested using aqueous and methanolic solvents. Methanol was found to provide heightened metabolite recovery with fewer interfering macromolecular signals compared to aqueous buffers, supporting its use as a preferred extraction solvent. Additional experimental variables, such as extraction time and the number of DBS punches, were optimized to improve spectral quality. Potentially interfering contaminations from sampling materials and consumables were identified. As a demonstration of practical application, DBS cards were distributed and returned via international and local transport, and their metabolic profiles were assessed. Despite some variation among transported samples, individual-specific metabolic signatures remained discernible, suggesting a robustness of the method for comparative analyses. Overall, these initial results support the use of NMR as a complementary technique to mass spectrometry for DBS-based metabolomics, particularly when simplicity, reproducibility, and robustness is prioritized, and when overall sensitivity is less of a factor.

Biological metal-organic frameworks (BioMOFs) demonstrate potential in sensing applications owing to their environmentally benign nature and non-toxic characteristics. In this work, a green Ce-BioMOF (Suc-Ce-OH) was synthesized via a one-step hydrothermal method using succinic acid ligands coordinated to Ce⁴⁺ metal centers. After simple alkaline treatment, the resulting Suc-Ce-OH exhibited outstanding phosphatase-like (PPA-like) activity, which could catalyze the hydrolysis of 4-methylumbellione phosphate disodium salt (4-MUP) and the dephosphorylation of 3-(2'-spiroadamantyl)-4 methoxy-4-(3'-phosphoryloxyphenyl)- 1,2-dioxetane (AMPPD) to generate blue fluorescent (FL) and strong chemiluminescence (CL) signals, respectively. Glyphosate with carboxyl group can inhibit PPA-like activity by consuming hydroxyl groups on the surface of Suc-Ce-OH, thus decrease the FL and CL intensities produced from hydrolysis of 4-MUP and AMPPD. Therefore, a FL-CL dual-mode detection method for glyphosate was established with low detection limit (LOD) of 0.081 μg mL^-1 and 0.038 μg mL^-1, respectively. This dual-mode detection method enables sensitive glyphosate detection with robust anti-interference in complex matrices and was successfully applied to the determination of glyphosate in real samples.

Hydrogen peroxide (H₂O₂) is a key signaling molecule in tumor progression, making its real-time detection vital for elucidating the complex mechanisms underlying tumorigenesis. Herein, we report a rationally colorimetric sensing platform for rapid tumor screening, leveraging the bifunctional enzyme-like activity of a heterostructured h-NiO/CoO/C nanosphere. Notably, by activating electron structure reconstruction with abundant oxygen vacancies and utilizing a dual-non-precious-metal method, h-NiO/CoO/C nanosphere enhances catalytic performance beyond the limitations of single-non-precious-metal-doped nanomaterials (e.g., NiO/C and CoO/C), remarkably boosting peroxidase (POD)-mimicking catalytic activities. Intriguingly, h-NiO/CoO/C shows a substantial enhancement in POD capability in comparison with single NiO/C and CoO/C, indicating superior sensitivity for monitoring endogenous H₂O₂. By integrating h-NiO/CoO/C with the chromogenic reaction principle, a highly rapid and sensitive endogenous H₂O₂ sensor is constructed. Furthermore, the resulting color change is analyzed via a smartphone application to provide instant, semiquantitative data. The smartphone-based colorimetric detection of H₂O₂ is realized via mutual verification by these two strategies. The assay data suggested that the POD-mimicking catalytic activity determination range is 0.01-2.8 mM, with a low limit of detection of 7.5 μM. This study demonstrates the rational design of highly efficient POD-mimicking nanozymes by engineering their structure-performance relationship, paving a new avenue for developing advanced nanozymes and providing a rapid, accessible toolkit for tumor screening.

A major obstacle in the development of solid contact ion-selective electrodes (SC-ISEs) is the frequent calibration procedures due to the low reproducibility of standard potential(E⁰) and the unstable signals. To address these challenges, we developed an all-solid state miniature sodium ion-selective electrode (Na⁺-ISE) based on acid-doped poly(3,4-ethylenedioxythiophene)-polystyrene sulphonate (PEDOT: PSS) as the solid contact layer, in combination with an external polarization technique. Acid doping minimized the Coulomb interaction between PEDOT and PSS, inducing significant phase separation and conformational re-aggregation of PEDOT chains, thus creating more contact points to facilitate charge transport and ion-to-electron transduction. The sensor exhibited excellent potentiometric performance with a detection limit of 5.90378 μM and potential drift of 10.99 μV/h. More importantly, external polarization significantly improved E⁰ reproducibility across different electrodes (standard deviation reduced from 57.41 mV to 1.95 mV) and reduced batch-to-batch E⁰ variability. The performance of the potentiometric sensor system was evaluated in inactivated fetal bovine serum, and the measurement results were highly comparable to those of the reference methods with deviation of less than 4 %. The electrochemical sensing system developed in this study provides a novel strategy for highly stable sodium ion sensing, indicating promising potential for calibration-free measurement in medical application.

The development of on-site Hg analysers is crucial for the rapid evaluation of Hg concentrations in environmental research. However, the fabrication of Hg analysers requires simplification of analytical procedures and device miniaturisation. Based on the above requirements, our research group previously investigated enclosed quartz cell cold vapour atomic absorption spectrometry (EQC-CV-AAS) as a base technique for an on-site Hg analyser. This study aimed to develop an on-site Hg analyser using three-dimensional (3D) printing technology, building upon the previously established EQC-CV-AAS method. The developed Hg analyser enabled on-site Hg analysis by incorporating 3D printing with identified analytical conditions (reductant volume: 0.05 mL, sample volume: 0.6 mL, stabilisation time: 7.0 min). The developed method exhibited analytical performance with a limit of detection of 0.59 μg/L, limit of quantification of 1.80 μg/L, and relative standard deviation of 5.00 %. Furthermore, the analytical performance of the developed method complied with the World Health Organisation recommendation for Hg in drinking water (6.00 μg/L), as demonstrated by on-site spike recovery tests of environmental water samples (river water and seawater).

The Novel Duck Reovirus (NDRV) seriously threatens the global poultry industry due to the lack of effective therapies. Preventive measures for NDRV heavily depend on early disease detection, highlighting the need for rapid and sensitive diagnostic methods. This study used Cas12a orthologs Gs12-18 to develop a visual CRISPR-based detection assay targeting the NDRV S3 gene. Comparative analysis of candidate Cas12a proteins, Gs12-16 and Gs12-18, showed that Gs12-18 has significantly better trans-cleavage activity, making it especially suitable for highly sensitive nucleic acid detection. We integrated Gs12-18 with loop-mediated isothermal amplification (LAMP) technology to create a LAMP-CRISPR/Gs12-18 detection platform. This method enables visual detection of the NDRV S3 gene with high specificity and sensitivity, with a detection limit of 38 copies per reaction. It does not require complex equipment and is suitable for point-of-care testing. This research provides a reliable diagnostic tool for the early prevention and control of NDRV.

Tea polyphenols are polyphenolic substances rich in catechol structures, therefore the nanozymes with enhanced catechol oxidase-like activity should be more suitable for the enhanced sensing of tea polyphenol, compared to other nanozymes with polyphenol oxidase-like activity. In this work, we prepared the nanozyme DBA-Cu with boronic acid structure with the enhanced ability for the sensing of tea polyphenols. It was found that the boric acid structure on the nanozyme was the key to enhance its catechol binding ability and catalytic rate. Based on the enhanced ability for the sensing of tea polyphenols as well as the fluorescence properties of DBA-Cu, a nanozyme-based sensor array was constructed for recognizing tea polyphenols and raw Pu-erh, which has a wide range of applications in different environments with rich catechol structures.

Gunshot residue (GSR) is defined as particles generated upon the discharge of ammunition from a firearm. The main components of ammunition include the primer, cartridge case, and bullet. GSR particles originated from a combination of these components as well as from internal firearm parts. For conventional ammunition, GSR can be reliably identified by detecting Pb, Ba, and Sb using scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). In contrast, GSR from nontoxic ammunition lacks these markers, making SEM-EDS detection ineffective. Laser-induced breakdown spectroscopy (LIBS) was used to analyze GSR-NTA particles collected directly from shooters' hands to identify potential chemical fingerprints. Spectra were acquired across two spectral ranges (186-1042 nm and 186-570 nm), and elements such as H, N, O, C, Ti, Zn, Cu, Ba, Sr, Fe, Mg, and Al were detected. Multivariate analysis and machine learning (ML) algorithms were applied. The dataset was divided into training and external validation sets, with linear discriminant analysis (LDA) achieving 100 % classification accuracy. Spectral analysis revealed that Zn, Ti, Cu, and Fe were the primary elements responsible for sample differentiation, with minor contributions from Ba and Sr. In conclusion, the combination of LIBS and ML shows potential as a forensic tool for identifying GSR-NTA particles on the hands of individuals who have, or have not, discharged a firearm.