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A guided ion beam tandem mass spectrometer was used to study the reactions of U+ with N2 and NO. Reaction cross sections were measured over a wide range of energy for both systems. In each reaction, UN+ is formed by an endothermic process, thereby enabling the direct measurement of the threshold energy and determination of the UN+ bond dissociation energy. For the reaction of U+ + N2, a threshold energy (E0) of 4.02 ± 0.11 eV was measured, leading to D0 (UN+) = 5.73 ± 0.11 eV. The reaction of U+ + NO yields UO+ through an exothermic, barrierless process that proceeds with 94 ± 23% efficiency at the lowest energy. Analysis of the endothermic UN+ cross section in this reaction provides E0 = 0.72 ± 0.11 eV and, therefore, D0 (UN+) = 5.78 ± 0.11 eV. Averaging the values obtained from both reactions, we report D0 (UN+) = 5.76 ± 0.13 eV as our best value (uncertainty of two standard deviations). Combined with precise literature values for the ionization energies of U and UN, we also derive D0 (UN) = 5.86 ± 0.13 eV. Both bond dissociation energies agree well with high-level theoretical treatments in the literature. The formation of UN+ in reaction of U+ with NO also exhibits a considerable increase in reaction probability above ∼3 eV. Theory suggests that this may be consistent with the formation of UN+ in excited quintet spin states, which we hypothesize are dynamically favored because the number of 5f electrons in reactants and products is conserved. [ABSTRACT FROM AUTHOR]

We designed a trigonal symmetric imine-linked covalent organic framework (COF), TFPC-DAB, with control over the angularity of the building units, where a bent C2-symmetric diamine, such as 1,3-diaminobenzene (1,3-DAB or DAB), with an exo-angle of 120° was used instead of those with an exo-angle of 180°, in combination with a C3-symmetric trialdehyde, such as tri(4-formylphenoxy)cyanurate (TFPC). Its synthesis was accomplished by reacting the building units in a mixture of mesitylene/dioxane/6 M acetic acid under solvothermal conditions. The phase purity, thermal stability, and porosity of TFPC-DAB were established by various analytical techniques. Utilizing the Density Functional Tight Binding (DFTB+) simulation and Pawley refinement, the best fit of the small angle x-ray pattern was found to have an AA stacking of TFPC-DAB in the trigonal space group P3 with low refinement parameters. Such smart materials are in huge demand to detect hazardous corrosive chemicals, such as HCl and NH3. The dual features of electron deficient π-acidic triazine moiety and heteroatoms (N/O) from TFPC and electron rich phenyl units from DAB embodied in the framework enhance its luminescent property and thereby make it suitable for solvent-based HCl and NH3 sensing. The detection limits for HCl and NH3 in methanol were found to be 14 and 82 ppb, respectively. The effect of solvent polarity on the sensing studies was observed with much lower detection limits in dioxane: 2.5 and 11 ppb for HCl and NH3, respectively. A detailed theoretical calculation using density functional theory and configurational bias Monte Carlo modules was conducted for understanding interactions between the COF and HCl or NH3 analytes. [ABSTRACT FROM AUTHOR]

The dynamic characteristics (i.e. autocorrelation and cross-correlation) in modern industrial systems have raised great challenges to process fault detection. To cope with the dynamics and uncertainty of dynamic industrial processes, this paper proposes a new process control method, dynamic convolutional gated recurrent unit attention auto-encoder (DCGRUA-AE) for fault detection in dynamic processes. Firstly, DCGRUA-AE integrates a convolutional gated recurrent unit (CGRU) with a local convolution layer to learn both global and local features of dynamic process data in an unsupervised fashion. Secondly, a dual attention module is embedded in the deep network to preserve effective features. Finally, DeconvGRU combined with a dense layer is used as the encoder to reconstruct the original process data. Two statistics (i.e. T-square (T2) and squared prediction error (SPE)) based on DCGRUA-AE are used to set the control limits for fault detection. The feasibility and superiority of DCGRUA-AE-based fault detection method have been verified on four industrial processes. The experimental results indicate that the CGRU and dual attention mechanism can significantly improve the fault detection performance of DCGRUA-AE in dynamic processes. The hybrid of CGRU, attention mechanism and auto-encoder provides a new method for fault detection in dynamic industrial processes. [ABSTRACT FROM AUTHOR]

In this work, it was found that organotin-functionalized tungstophosphates PW9-TM-SnRCOO and P2W15-TM-SnRCOO (PW9 = [PW9O34]9−; P2W15 = [P2W15O56]12−; TM = Mn, Co, Zn; R = CH2CH2) exhibited mimicking horseradish peroxidase (HRP) activity, with the catalytic activity of PW9-TM-SnRCOO being higher than that of P2W15-TM-SnRCOO. Among the polyoxometalates (POMs), those containing Zn ions demonstrated the highest catalytic activity. Furthermore, a recyclable POM-based ZIF-nanocomposite, Na8K2[Zn2{Sn(CH2)2COO}2(B-α-PW9O34)2]·13H2O@ZIF-67 (PW9-Zn-SnRCOO@ZIF-67), was designed and synthesized using a convenient one-step method at room temperature. As a mimic enzyme of HRP for the catalytic oxidation of o-phenylenediamine (OPD), PW9-Zn-SnRCOO@ZIF-67 exhibited enhanced catalytic activity and anti-interference ability. Moreover, the introduction of the POM-estertin derivative significantly improved the acid resistance of ZIF-67. PW9-Zn-SnRCOO@ZIF-67 can be further used as a colorimetric sensor material for the detection of acetone with a wide linear range (0.01–4.0 mM), a low detection limit (0.0074 mM), and good reusability. These results demonstrate that organotin-functionalized POMs@ZIFs, as a new class of non-enzymatic sensor materials, have wide application prospects for the detection of acetone in real water samples. [ABSTRACT FROM AUTHOR]

Bile acid (BA) is one of the main active components of bile and has multiple isomers, the structure or content of its isomers often changes due to diseases and other health problems; thus, the accurate detection of BA isomers is very important. In this study, two groups of BA isomers of glycine-conjugated BAs and taurine-conjugated BAs were simultaneously separated and quantitatively analyzed by ion mobility mass spectrometry (IM-MS). Especially, baseline mobility separation between the isomers was achieved by the formation of binary complexes via simple interaction with spiramycin (SPM), for which a separation resolution (Rp-p) of 1.96 was reached. Moreover, BA isomers were quantitatively analyzed, and the limit of detection (LOD) of absolute quantification for TCDCA/TUDCA and GUDCA/GCDCA/GHDCA was 0.514 and 0.611 ng∙mL−1, respectively; the LODs for molar ratio ranges of relative quantification for TCDCA/TUDCA, GUDCA/GHDCA, and GCDCA/GHDCA were 1:18–30:1, 1:18–21:1, and 1:19–21:1, respectively. Additionally, BA isomers analyzed in pig bile powder and bear bile powder were measured, which were in good consistency with those labeled, revealing the differences in BA composition and content between the two powders. Finally, BA detection and recovery analyses were performed on serum samples, with a recovery rate of ≥73.69%, RSD of ≤6.8%, and SR (standard deviation of recoveries, the degree of difference between measured values and average recovery) of ≤1.27. Due to the simple, rapid, and lack of need for complex sample preparation and chromatographic separation, the proposed method can be an effective method for BA detection in practical samples. [ABSTRACT FROM AUTHOR]

As a kind of mycotoxin, aflatoxin B1 (AFB1), which is often found in agricultural products, poses a threat to human health. Developing a simple sensitive method for AFB1 detection is in great demand. Here, we reported an aptamer-based fluorescence assay for AFB1 detection by using DNAzyme to generate and amplify a signal. We redesigned a pair of DNA sequences, which originated from the anti-AFB1 aptamer and RNA-cleaving DNAzyme 10–23. In the absence of AFB1, the aptamer hybridized with the region of the substrate-binding arm of the DNAzyme, inhibiting the activity of the DNAzyme. In the presence of AFB1, the binding of AFB1 to the aptamer led to the displacement of the DNAzyme from the aptamer. The substrate-binding arm was unblocked, and the activity of the DNAzyme was restored for the hydrolysis of the fluorophore and quencher-labeled substrate, causing a significant fluorescence increase. This assay could detect AFB1 in the dynamic range from 0.98 to 2000 nmol/L with high selectivity, and the detection limit was 0.98 nmol/L. Moreover, the assay was able to detect AFB1 in a complex sample matrix. This work provides a useful tool for the analysis of AFB1. [ABSTRACT FROM AUTHOR]

CRISPR/Cas systems are increasingly utilized for sensitive miRNA detection through enzyme-based pre-amplification. To address challenges such as high costs, non-specific amplification, and interference from primer residues in pre-amplification strategies, herein a dual amplification CRISPR miRNA assay was developed by combining enzyme-free HCR with single-particle analysis. Attomolar detection limits, excellent selectivity, and practicability were achieved by applying this method. [ABSTRACT FROM AUTHOR]

Sample preparation presents a major challenge in point-of-care (POC) diagnostic assays, including ones requiring whole blood as the starting specimen. This study presents an integrated sample preparation device -- which we call PRECISE -- that performs both plasma separation and nucleic acid extraction, enabling streamlined sample preparation from whole blood requiring only a commercially available blood collection tool and a syringe, and no other external equipment or electricity. Plasma separation is performed using a dual-membrane filter (which filters out blood components while limiting membrane clogging) integrated into the cartridge, and nucleic acid extraction is performed by users moving magnets (to mix the samples, and along a guided track). The plasma filtration demonstrated recovery on par with lab-based centrifugation, and the extraction module showed performance similar to benchtop-based magnetic bead extraction. A sample-to-result demonstration on 50 μL of whole blood spiked with virions of hepatitis C virus (HCV), operating the PRECISE cartridge in 16 minutes followed by benchtop PCR, showed a limit of detection (~6770 IU mL-1) on the order of the minimal requirements of target product profile for POC HCV detection. Future work on the PRECISE cartridge, building on POC accessibility and fast sample preparation demonstrated in this work, may enable detection of bloodborne pathogens from whole-blood specimens collected at the POC. [ABSTRACT FROM AUTHOR]

The increasing demand in healthcare for accessible and cost-effective analytical tools is driving the development of reliable platforms to the customization of therapy according to individual patient drug serum levels, e.g. of anti-psychotics in schizophrenia. A modifier-free microfluidic paper-based electroanalytical device (μPED) holds promise as a portable, sensitive, and affordable solution. While many studies focus on the working electrode catalysts, improvements by engineering aspects e.g. of the electrode arrangement are less reported. In our study, we demonstrate the enhanced capabilities of the 3D electrode layout of μPED compared to 2D μPED arrangements. We especially show that screen printing can be employed to prepare 3D μPEDs. We conducted a comparison of different 2D and 3D electrode arrangements utilizing cyclic voltammetry in [Fe(CN)6]3−/4−, along with square-wave voltammetry for clozapine (CLZ) sensing. Our findings reveal that the utilization of the 3D μPED leads to an increase in both the electrochemically active surface area and the electron transfer rate. Consequently, this enhancement contributes to improve sensitivity in the CLZ sensing. The 3D μPED clearly outperforms the 2D μPED arrangement in terms of signal strength. With the 3D μPED under the optimized conditions, a linear dose–response for a concentration range from 7.0 to 100 μM was achieved. The limit of detection and sensitivity was determined to be 1.47 μM and 1.69 μA μM−1 cm−2, respectively. This evaluation is conducted in the context of detection and determination of CLZ in a human blood serum sample. These findings underscore the potential of the 3D μPED for future applications in pharmacokinetic analyses and clinical tests to personalize the management of schizophrenia. [ABSTRACT FROM AUTHOR]

Black carbon (BC) generated from vehicle engine exhaust is a global environmental concern and a freely available carbon source. Herein, onion-like nanocarbon (ONC) isolated from diesel soot (DS) has been surface-functionalized with a small amine named ethylenediamine (en). The amine-functionalized ONC designated as f-en-ONC shows maximum emission at 430 nm under excitation at 350 nm. The aqueous solution of f-en-ONC emits a blue color on UV-light illumination and displays a quantum yield of ∼18%. Among the different tested biomolecules, f-en-ONC selectively detects glutamic acid (GLA) through fluorescence-based quenching. The limit of detection for GLA was found to be ∼ 17.3 μM. Based on spectral overlap studies, UV-visible spectra, and the Stern–Volmer plot, the dynamic quenching mechanism was suggested for the fluorescence-based sensing of GLA. Further, the water-soluble f-en-ONC was used as a bioimaging probe for cancer cells. [ABSTRACT FROM AUTHOR]

As a new type of artificial enzyme, a nanozyme is an ideal substitute for natural enzymes and has been successfully applied in many fields. However, in the application of biomolecular detection, most nanozymes have the disadvantages of long reaction times or high detection limits, prompting researchers to search for new efficient nanozymes. In this work, the enzyme-like activities of three polyoxometalate-based iron-organic complexes ([Fe(bpp)2](Mo6O19), [Fe(bpp)2]2(Mo8O26)·2CH3OH, and [Fe(bpp)2]4H[Na(Mo8O26)]3), namely, FeMo6, Fe2Mo8, and Fe4Mo8Na, were analyzed. All three polyoxometalate-based iron-organic complexes were found to be capable of catalyzing hydrogen peroxide (H2O2) to oxidize 3,3′,5,5′-tetramethylbenzidine and o-phenylenediamine, resulting in visible color changes, further exhibiting peroxidase-like activity. Results showed that Fe4Mo8Na had more active sites due to its long chain structure, endowing more prominent peroxidase-like activity compared with Fe2Mo8 and FeMo6. A colorimetric sensing platform for H2O2 and ascorbic acid detection based on Fe4Mo8Na was established. The linear response range for H2O2 detection was 0.5–100 μM, and the detection limit was 0.143 μM. The linear response for ascorbic acid detection ranges from 0 to 750 μM with a detection limit of 1.07 μM. This study provides a new perspective for developing new nanozymes and expanding the sensing and detection application of nanozymes. [ABSTRACT FROM AUTHOR]

Nanozymes are nanomaterials with mimetic enzyme properties and the related research has attracted much attention. It is of great value to develop methods to construct nanozymes and to study their application in bioanalysis. Herein, the metal–ligand cross-linking strategy was developed to fabricate superstructure nanozymes. This strategy takes advantage of being easy to operate, adjustable, cheap, and universal. The fabricated superstructure nanozymes possess efficient peroxidase-like catalytic activity. The enzyme reaction kinetic tests demonstrated that for TMB and H2O2, the Km is 0.229 and 1.308 mM, respectively. Furthermore, these superstructure nanozymes are applied to highly efficient and sensitive detection of glucose. The linear range for detecting glucose is 20–2000 μM, and the limit of detection is 17.5 μM. Furthermore, mechanistic research illustrated that this integrated system oxidizes glucose to produce hydrogen peroxide and further catalyzes the production of ·OH and O2·–, which results in a chromogenic reaction of oxidized TMB for the detection of glucose. This work could not only contribute to the development of efficient nanozymes but also inspire research in the highly sensitive detection of other biomarkers. [ABSTRACT FROM AUTHOR]

Nanoceria have demonstrated a wide array of catalytic activity similar to natural enzymes, holding considerable significance in the colorimetric detection of alkaline phosphatase (ALP), which is a biomarker of various biological disorders. However, the issues of physiological stability and formation of protein corona, which are strongly related to their surface chemistry, limit their practical application. In this work, CeO2 nanoparticles characterized by enhanced dimensional uniformity and specific surface area were synthesized, followed by encapsulation with various polymers to further increase catalytic activity and physiological stability. Notably, the CeO2 nanoparticles encapsulated within each polymer exhibited improved catalytic characteristics, with PAA-capped CeO2 exhibiting the highest performance. We further demonstrated that the PAA-CeO2 obtained with enhanced catalytic activity was attributed to an increase in surface negative charge. PAA-CeO2 enabled the quantitative assessment of AA activity within a wide concentration range of 10 to 60 μM, with a detection limit of 0.111 μM. Similarly, it allowed for the evaluation of alkaline phosphatase activity throughout a broad range of 10 to 80 U/L, with a detection limit of 0.12 U/L. These detection limits provided adequate sensitivity for the practical detection of ALP in human serum. [ABSTRACT FROM AUTHOR]

The development of cost-effective and highly efficient electrocatalysts is critical to help electrochemical non-enzymatic sensors achieve high performance. Here, a new class of catalyst, Ru single atoms confined on Cu nanotubes as a single-atom alloy (Ru1Cu NTs), with a unique electronic structure and property, was developed to construct a novel electrochemical non-enzymatic glucose sensor for the first time. The Ru1Cu NTs with a diameter of about 24.0 nm showed a much lower oxidation potential (0.38 V) and 9.0-fold higher response (66.5 μA) current than Cu nanowires (Cu NWs, oxidation potential 0.47 V and current 7.4 μA) for glucose electrocatalysis. Moreover, as an electrochemical non-enzymatic glucose sensor, Ru1Cu NTs not only exhibited twofold higher sensitivity (54.9 μA mM−1 cm−2) and wider linear range (0.5–8 mM) than Cu NWs, but also showed a low detection limit (5.0 μM), excellent selectivity, and great stability. According to theoretical calculation results, the outstanding catalytic and sensing performance of Ru1Cu NTs could be ascribed to the upshift of the d-band center that helped promote glucose adsorption. This work presents a new avenue for developing highly active catalysts for electrochemical non-enzymatic sensors. [ABSTRACT FROM AUTHOR]

Laccase is an enzyme known for its eco-friendly uses in environmental cleanup and biotechnology. However, it has limitations such as low stability, high cost, and complex recycling. So, there is a need for laccase mimics that can effectively imitate its properties. Herein, we created copper formate–lysine nanoparticles (Cuf-Lys) that mimic laccase's activity. The developed Cuf-Lys demonstrated remarkable polyphenol oxidase-like activity, stability, and recyclability, making them suitable for the fabrication of efficient colorimetric sensors for the detection of epinephrine. These sensors had a specific response and could accurately measure epinephrine concentrations ranging from 2.5 to 50 μM, with a detection limit as low as 1 μM. Furthermore, the biosensor demonstrated high sensitivity and selectivity when applied to the detection of rutin. The limit of detection for rutin was determined to be 0.16 μM while in the linear concentration range of 0.25 to 150.0 μM. We believe that Cuf-Lys provide a new route for the design of laccase mimics, showing potential applications for biomedical diagnosis and environmental monitoring. [ABSTRACT FROM AUTHOR]

Nanozyme technology has gained significant regard and been successfully implemented in various applications including chemical sensing, bio-medicine, and environmental monitoring. Fe-CDs were synthesized and characterized well in this study. As compared to HRP (3.7 mM), the Fe-CDs exhibited a higher affinity towards H2O2 (0.2 mM) using the steady-state kinetic assay and stronger catalytic capability by changing the color of TMB to the blue color of the oxidized state, oxTMB. Additionally, an efficient peroxidase mimic, Fe-CDs/GOx, based on the hybrid cascade system to produce in situ H2O2 for the visual detection of glucose (color change: colorless to blue, and then to green), has been developed in detail, with limits of detection (LODs) for H2O2 and glucose of 0.33 μM and 1.17 μM, respectively. The changes further demonstrate a linear relationship between absorbance and H2O2 concentration, ranging from 10 to 60 μM, and for glucose (1 to 60 μM). To assess the accuracy and detection capability of the Fe-CDs/GOx system, we evaluated a real human serum sample obtained from adult males in a local hospital. In conclusion, Fe-CDs serving as a peroxidase mimic have the potential for various applications in the fields of biomedicine and nanozymes. [ABSTRACT FROM AUTHOR]

α-Glucosidase (α-Glu) is implicated in the progression and pathogenesis of type II diabetes (T2D). In this study, we developed a rapid colorimetric technique using platinum nanoparticles stabilized by chitosan (Ch-PtNPs) to detect α-Glu activity and its inhibitor. The Ch-PtNPs facilitate the conversion of 3,3′,5,5′-tetramethylbenzidine (TMB) into oxidized TMB (oxTMB) in the presence of dissolved O2. The catalytic hydrolysis of 2-O-α-d-glucopyranosyl-l-ascorbic acid (AA-2G) by α-Glu produces ascorbic acid (AA), which reduces oxTMB to TMB, leading to the fading of the blue color. However, the presence of α-Glu inhibitors (AGIs) hinders the generation of AA, allowing Ch-PtNPs to re-oxidize colorless TMB back to blue oxTMB. This unique phenomenon enables the colorimetric detection of α-Glu activity and AGIs. The linear range for α-Glu was found to be 0.1–1.0 U mL−1 and the detection limit was 0.026 U mL−1. Additionally, the half-maximal inhibition value (IC50) for acarbose, an α-Glu inhibitor, was calculated to be 0.4769 mM. Excitingly, this sensing platform successfully detected α-Glu activity in human serum samples and effectively screened AGIs. These promising findings highlight the potential application of the proposed strategy in clinical diabetes diagnosis and drug discovery. [ABSTRACT FROM AUTHOR]

Although traditional Fe-based nanozymes have shown great potential, generally only a small proportion of the Fe atoms on the catalyst's surface are used. Herein, we synthesized single-atom Fe on N-doped graphene nanosheets (Fe-CNG) with high atom utilization efficiency and a unique coordination structure. Active oxygen species including superoxide radicals (O2•−) and singlet oxygen (1O2) were efficiently generated from the interaction of the Fe-CNG with dissolved oxygen in acidic conditions. The Fe-CNG nanozymes were found to display enhanced oxidase-like and laccase-like activity, with Vmax of 2.07 × 10−7 M∙S−1 and 4.54 × 10−8 M∙S−1 and Km of 0.324 mM and 0.082 mM, respectively, which is mainly due to Fe active centers coordinating with O and N atoms simultaneously. The oxidase-like performance of the Fe-CNG can be effectively inhibited by ascorbic acid (AA) or hydroquinone (HQ), which can directly obstruct the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB). Therefore, a direct and sensitive colorimetric method for the detection of AA and HQ activity was established, which exhibited good linear detection and limit of detection (LOD) of 0.048 μM and 0.025 μM, respectively. Moreover, a colorimetric method based on the Fe-CNG catalyst was fabricated for detecting the concentration of AA in vitamin C. Therefore, this work offers a new method for preparing a single-atom catalyst (SAC) nanozyme and a promising strategy for detecting AA and HQ. [ABSTRACT FROM AUTHOR]

Human urine phosphorus (existing in the form of phosphate) is a biomarker for the diagnosis of several diseases such as kidney disease, hyperthyroidism, and rickets. Therefore, the selective detection of phosphate in urine samples is crucial in the field of clinical diagnosis. Herein, we reported the phosphatase-like catalytic activity of few-layered h-BNNS for the first time. As the phosphatase-like activity of few-layered h-BNNS could be effectively inhibited by phosphate, a selective fluorescent method for the detection of phosphate was proposed. The linear range for phosphate detection is 0.5–10 µM with a detection limit of 0.33 µM. The fluorescent method was then explored for the detection of human urine phosphorus in real samples. The results obtained by the proposed method were consistent with those of the traditional method, indicating that the present method has potential application for urine phosphorus detection in clinical disease diagnosis. [ABSTRACT FROM AUTHOR]

The room temperature gas sensor has attracted sufficient attention due to the fact that low-power products are more suitable for practical environments. However, developing gas sensors with low detection limits remains challenging. In this paper, a room-temperature sensor was prepared by in situ growth of WO 3 nanospheres on SnO 2 inverse opal (IO) by aerosol assisted chemical vapor deposition (AACVD) method, detecting ppb level of ammonia. The WO 3 nanospheres are directly fabricated on IO, and their elemental composition, morphology and structure is characterized using XRD, SEM and TEM. The results show that WO 3 nanospheres have been prepared on SnO 2 IO successfully. It showes that the WO 3 /SnO 2 (WS) type sensor has a detection limit as low as 1 ppb at room temperature from the gas sensitivity data. In addition, the sensor's response value to 100 ppm NH 3 reached 65 %. Its excellent sensing performance depends on the distinctive morphology features of WO 3 and SnO 2. The hierarchical characteristic effectively enhances the sensing performance for NH 3. Consequently, this presents a feasible solution for fabricating the room temperature NH 3 sensor. [ABSTRACT FROM AUTHOR]

N-methyl pyrrolidone (NMP) is an important organic compound that is widely used in many industrial fields. Due to its volatility and toxicity, the detection of NMP content becomes crucial. Plasma treatment is an efficient method that utilizes high-energy ions generated by plasma to change the surface properties of materials, which can dramatically improve the performance of gas sensors. In this paper, ZnO nanorods were in-situ grown on ceramic tubes via hydrothermal method, followed by oxygen plasma treatment for different time, and the gas-sensing performance of the treated ZnO nanorods was investigated. In addition, the density functional theory calculation was used to explore the potential mechanism for the improvement of gas-sensing performance. The results show that ZnO treated with oxygen plasma for 60 s has more oxygen vacancies (45.53 %) and higher adsorption energy (−1.06 eV) to NMP. The ZnO-60 gas sensors have excellent selectivity to 100 ppm NMP at 210 °C, with a response value up to 197.58, low detection limit (94 ppb), and short response/recovery time (75 s/27 s). This study not only provides important theoretical and experimental basis for further optimizing the design and manufacture of gas sensors, but also provides strong support for environmental monitoring and human health protection. [Display omitted] • ZnO nanorods were prepared on the ceramic tubes by in-situ growth method. • Oxygen plasma treatment was used to improve the content of oxygen vacancies (45.53 %) for ZnO nanorods and the high gas-sensing response (S r = 197.58) to NMP with a detection limit of 94 ppb was achieved. • The adsorption energy, charge density difference, and density of states of NMP on the surface of ZnO materials were simulated and calculated by the DFT study to verify the potential mechanism for improving gas-sensing performance. • The sensors exhibit high selectivity and stability with short response/recovery time. [ABSTRACT FROM AUTHOR]

The enzyme-like activity of noble metal nanomaterials has been widely demonstrated. However, as an important noble metal, iridium (Ir) and its alloy nanomaterials have been less studied, particularly regarding the effect of Ir content on enzyme-like activity. Here, we demonstrated for the first time that a low Ir content can greatly improve the peroxidase-like activity of Pt-based nanozymes. When the weight percentage of Ir was 3.45% in trimetallic PtAuIr hollow nanorods (HNRs) and 2.86% in bimetallic PtIr HNRs, their specific activity increased by approximately 70% compared to their PtAu and Pt counterparts, respectively. However, a slightly higher percentage of Ir significantly diminished the enhancement effect on their specific activity. Density functional theory (DFT) calculations show that the rate-determining step (RDS) energy barrier of the nanozyme with low Ir content is lower than that of the nanozyme with slightly higher Ir content. Furthermore, we studied the kinetic properties of the PtAuIr nanozyme using TMB as the substrate. Its Michaelis–Menten constant (Km) and Vmax were 1.756 mM and 2.152 × 10−6 M s−1, respectively. Additionally, a colorimetric detection platform based on the PtAuIr nanozyme was established and applied to detect o-phenylenediamine (OPD), with a detection limit as low as 0.076 μM. This study highlights the important role of the Ir content in Pt-based nanozymes and demonstrates that PtAuIr nanozymes have potential applications in environmental detection. [ABSTRACT FROM AUTHOR]

A functionalized Hf(IV)-based metal–organic framework (MOF) was synthesized, characterized, and successfully employed as a highly sensitive and selective fluorometric sensor for (1,1-diamino-2,2-dinitroethylene) FOX-7, which is a significant nitro explosive. The fluorescent sensor (MOF), denoted as CSMCRI-KNC′, exhibited a turn-off fluorescence signal towards FOX-7 in a water medium even in the presence of other potentially competitive explosives. The limit of detection (LOD) value for the detection of FOX-7 is fairly low (189 nM), and the response time is extremely rapid (<20 s). The sensing mechanism was investigated in detail and found to be based on non-covalent interactions, fluorescence resonance energy transfer (FRET), and photo-induced electron transfer (PET) processes. The sensing medium (water), detection time, sensitivity, and selectivity demonstrate the great potential of CSMCRI-KNC′ in the fluorescence-based sensor field. Additionally, the MOF was utilized as an efficient, recyclable, and heterogeneous catalyst for Knoevenagel condensation between barbituric acid and aromatic aldehydes in the presence of ethanol in an eco-friendly reaction medium. The present catalytic methodology has several attractive features, including mild reaction conditions, a short reaction time, high atom economy, and tolerance of various functional moieties. The catalyst could be recovered and reused successively without any remarkable loss in its catalytic activity. Moreover, the "hot filtration method (Sheldon's test)" has also been established to ensure the heterogeneity of the catalyst. Furthermore, the plausible mechanism of the catalysis is well presented. [ABSTRACT FROM AUTHOR]

Ethylene glycol (EG) is a widely used material, but its vapor is harmful to human health already in low concentrations. Thus, highly sensitive EG gas sensors are urgently needed. Herein, a series samples of ZnO and carbon dots (CDs) were synthesized at different ratios through a simple mechanical grinding method. The senor made using ZnO/CDs2 exhibits an ultra-high response (Ra/Rg) to 100 ppm EG up to 2798, 1378 and 467, and extremely low detection limit as low as 21 ppb, 13 ppb and 2 ppb, under UV light, visible light, and infrared light, respectively, as well as excellent repeatability and long-term stability. Especially, under UV light irradiation, the response of ZnO/CDs2 to 100 ppm EG is 24 times that of pure ZnO (Ra/Rg = 114.7), and more than 71 times that of 9 other gases. The outstanding gas sensing performance of ZnO/CDs2 can be attributed to the excellent light response ability of CDs at first, which greatly enriches the electron concentration in ZnO/CDs under light irradiation. Furthermore, the photo-induced electron transfer (PET) property of CDs and the p-n heterojunction formed at the interface between ZnO and CDs play a key role in rapid electron transport and transfer, avoiding a large number of electron hole recombination. [ABSTRACT FROM AUTHOR]

A sensitive, rapid, efficient, inexpensive, and easy-to-use vortex-assisted eutectic solvent microextraction process was extended to quantify Ponceau-4R (PN4R) in beverage samples followed by spectrophotometric detection. Here, a green solvent consisting of tetrabutylammonium bromide: n-octanol at a ratio of 1:3 was tested in the PN4R microextraction process. Also, different parameters affecting PN4R quantification through deep eutectic solvent in the microextraction model, including microliter volumes of extraction solvent, concentration of salt, extraction time, and pH were studied using multivariate procedures. Using this model, the maximum response was achieved with a eutectic solvent volume of 262 μL, extraction time of 5.3 min, pH 6.7, and 0.9% salt with Desirability = 1. The linear range was determined in optimum conditions to be from 15 to 1200 μg L−1. The enrichment factor and limit of detection were achieved to be 50-fold and 4.5 μg L−1, respectively. The limit of quantitation was 15 μg L−1. To monitor PN4R, this model has been used in fruit juice samples with favorable recoveries in the range of 97.8%–101%. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are known to bioaccumulate in aquatic organisms, such as shellfish, and have been linked to adverse human health outcomes. Increasing attention has been focused on method development for the detection of PFAS in various media; however, these methods are typically tedious, require high solvent volumes, and are time consuming. The present method used a Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) extraction approach and analysis by ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) to detect 28 PFAS in Eastern oyster (Crassostrea virginica) tissue. This method was validated using limit of detection, limit of quantitation, and precision and accuracy studies. Limits of detection ranged from 0.2 to 5.8 ng g−1, limits of quantitation ranged from 0.66 to 19.2 ng g−1, and recoveries spanned 52.1–105.9% at the 100 ng mL−1 analyte level. Analysis of 12 unknown oyster composite samples revealed the detection of PFHxA, PFPeS, PFOA, PFHpA and PFOS and at least two compounds were detected in each oyster sample. This validated method proved to be an efficient and environmentally friendly sample preparation method for PFAS analysis in complex tissue media, such as oysters. [ABSTRACT FROM AUTHOR]

A novel technique for effervescent-based dispersive liquid–liquid microextraction is reported. Rapid and continuous effervescence, driven by hydrogen bubbles, was utilized to transfer the analyte from the aqueous to the organic phase. The reactivity of magnesium metal with water was exploited to generate a stream of hydrogen bubbles. In this method, an aqueous sample solution, contained in a microcentrifuge tube, was treated with 1 mg of magnesium and 100 µl of 1-undecanol. Microextraction was initiated by the addition of 100 µl of 1 M sodium bicarbonate to induce a rapid stream of hydrogen bubbles. The microcentrifuge tube was cooled to allow the solidification of 1-undecanol which was carefully separated and analyzed. Factors potentially affecting extraction efficiency were optimized, including the magnesium mass, concentration of sodium bicarbonate, extraction time, pH, open/closed system, sample volume, temperature, and analyte concentrations. These studies revealed the required speed and minimum concentration of sodium bicarbonate, as well as the possibility of efficient microextraction without sodium bicarbonate but in acidic conditions or at elevated temperatures (45–50 °C). The analytical performance was assessed and demonstrated to be promising. In the case of the model drug quercetin, the limit of detection (LOD) was determined to be 0.051 µg/ml, the limit of quantification (LOQ) was 0.154 µg/ml, and the extraction efficiency was 100%. The applicability of this method was also evaluated on samples with variable physicochemical properties, demonstrating an automated, fast, and efficient liquid–liquid microextraction protocol. [ABSTRACT FROM AUTHOR]

This work proposed an easy-to-perform but effective strategy to eliminate the ACQ effect of PAHs for ECL enhancement by coordinatively grafting PAH-derived ligands onto ultrathin MOLs, which opened a new horizon to develop high-efficiency Ru-complex-free porous ECL materials for fabricating supersensitive ECL sensing platforms. [Display omitted] • A novel ECL emitter was prepared by coordinatively grafting a new ECL luminophore PyTS on ultrathin MOL. • This work proposed a new and facile strategy to surmount the ACQ effect of PAHs. • This strategy provided significant inspiration for designing high-efficiency Ru-complex-free ECL materials. • The fabricated ECL biosensor accomplished the supersensitive detection of miRNA-21. The exploration of novel electrochemiluminescence (ECL) luminophores with excellent ECL properties is a current research hotspot in the ECL field. Herein, a novel high-efficiency Ru-complex-free ECL emitter PyTS-Zr-BTB-MOL has been prepared by using porous ultrathin Zr-BTB metal–organic layer (MOL) as carrier to coordinatively graft the cheap and easily available polycyclic aromatic hydrocarbon (PAH) derivative luminophore PyTS whose ECL performance has never been investigated. Gratifyingly, the ECL intensity and efficiency of PyTS-Zr-BTB-MOL were markedly enhanced compared to both PyTS monomers and PyTS aggregates. The main reason was that the distance between pyrene rings was greatly expanded after the PyTS grafting on the Zr 6 clusters of Zr-BTB-MOL, which overcame the aggregation-caused quenching (ACQ) effect of PyTS and thus enhanced the ECL emission. Meanwhile, the porous nanosheet structure of PyTS-Zr-BTB-MOL could distinctly increase the exposure of PyTS luminophores and shorten the diffusion paths of coreactants and electrons/ions, which effectively promoted the electrochemical excitation of more PyTS luminophores and thus achieved a further ECL enhancement. In light of the remarkable ECL property of PyTS-Zr-BTB-MOL, it was employed as an ECL indicator to build a novel high-sensitivity ECL biosensor for microRNA-21 determination, possessing a satisfactory response range (100 aM to 100 pM) and an ultralow detection limit (10.4 aM). Overall, this work demonstrated that using MOLs to coordinatively graft the PAH derivative luminophores to eliminate the ACQ effect and increase the utilization rate of the luminophores is a promising and efficient strategy to develop high-performance Ru-complex-free ECL materials for assembling ultrasensitive ECL biosensing platforms. [ABSTRACT FROM AUTHOR]

In contrast to natural enzymes, nanozymes show promising advantages of low cost and high stability for analytical applications. The simple mix of L -phenylalanine (F) and Cu2+ produces two-dimensional nanosheets of a coordination polymer with a high surface area ratio and rich exposed active sites as a novel catalyst. As the mimetic of natural laccase, this nanozyme (F–Cu) can catalyze the oxidative coupling reaction of 2,4-dichlorophenol (2,4-DP) and 4-aminoantipyrine (4-AP) to produce a distinct red product, thus establishing an intuitive and simple method for the detection of thiram. In the range of 0–7.5 μM, the absorbance intensity was linearly related to the concentration of thiram, and the detection limit was 0.0845 μM. The F–Cu nanozyme was successfully applied to the colorimetric detection of thiram in real samples. [ABSTRACT FROM AUTHOR]

Listeriamonocytogenes (L. monocytogenes) is a prevalent food-borne pathogen that can cause listeriosis, which manifests as meningitis and other symptoms, potentially leading to fatal outcomes in severe cases. In this study, we developed an aptasensor utilizing carboxylated magnetic beads and Cas12a to detect L. monocytogenes. In the absence of L. monocytogenes, the aptamer maintains its spatial configuration, keeping the double-stranded DNA attached and preventing the release of a startup template and activation of Cas12a's trans-cleavage capability. Conversely, in the presence of L. monocytogenes, the aptamer undergoes a conformational change, releasing the double-stranded DNA to serve as a startup template, thereby activating the trans-cleavage capability of Cas12a. Consequently, as the concentration of L. monocytogenes increases, the observable brightness in a blue light gel cutter intensifies, leading to a rise in fluorescence intensity difference compared to the control. This Cas12a aptasensor demonstrates excellent sensitivity towards L. monocytogenes, with a lowest detection limit (LOD) of 57.15 CFU/mL and a linear range of 4×102 to 4×107 CFU/mL (R2=0.9858). Notably, the proposed Cas12a aptasensor exhibited outstanding selectivity and recovery in beef samples, and could be employed for precise monitoring. This Cas12a aptasensor not only provides a novel fluorescent and visual rapid detection method for L. monocytogenes but also offers simplicity, speed, and stability compared to previous detection methods. Furthermore, it is suitable for on-site detection of beef samples. [ABSTRACT FROM AUTHOR]

Commercial automation systems for small- and medium-sized laboratories, including research environments, are often complex to use. For liquid handling systems (LHS), development is required not only for the robot's movements but also for adapting the bioanalytical method to the automated system. This study investigates whether a more human-like automation strategy—using a robotic system (RS)—is more suitable for research laboratories than a professional automation approach utilizing a commercial automated LHS. We conducted a series of measurements for protein determination using a Bradford assay manually, with a fully automated LHS, and with our human-like RS. Although the hand-like RS approach requires more than twice the time of the LHS, it achieved the best standard deviation in this setup (RS = 0.5, manual = 0.71, LHS = 0.86). Due to the low limit of detection (LOD) and limit of quantification (LOQ), most protein samples could be quantified with the RS (samples below LOQ = 9.7%, LOD = 0.23; LOQ = 0.25) compared to manual (samples below LOQ = 28.8%, LOD = 0.24; LOQ = 0.26) and the LHS (samples below LOQ = 36.1%, LOD = 0.27; LOQ = 0.31). In another time-dependent enzymatic assay test, the RS achieved results comparable to the manual method and the LHS, although the required time could be a constraint for short incubation times. Our results demonstrate that a more hand-like automation system closely models the manual process, leading easier to accurate bioanalytical results. We conclude that such a system could be more suitable for typical research environments than a complex LHS. [ABSTRACT FROM AUTHOR]

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Higher sensitivity with specific recognition of a sensor could ease the burden of sample purification or labelling procedure for specific testing and detection and there appear two methods including surface enhanced infrared absorption (SEIRA) and surface enhanced Raman scattering (SERS), promising better sensitivity and specificity, simultaneously, via detection of molecular footprints. Furthermore, researchers employ Fano resonance to further boost the detection limit of SEIRA by coupling between two absorption bands from molecules and metamaterials. Still, the current metamaterial absorbers are almost narrow band and require a specific design, only suitable for limited chemicals. Thus, in this work, we would like to design a broadband oblique-wire-bundle (OWB) metamaterial absorber (MA) which could interact with multiple functional groups' absorption from a sample, thus easing the burden of custom-made resonators. In experiments, indeed, our designed OWB MA developed four Fano resonance responses with three PMMAs' functional groups and one function group from carbon dioxide. The counterpart planar MA also performed SEIRA yet without occurrence of Fano resonance as a comparison. We believe this proposed OWB MA could facilitate the development of rapid detection in the field of food safety and chemical detection. [ABSTRACT FROM AUTHOR]

The integration of advanced materials and photonic nanostructures can lead to enhanced biodetection capabilities, crucial in clinical scenarios and point‐of‐care diagnostics, where simplified strategies are essential. Herein, a molecularly imprinted polymer (MIP) photonic nanostructure is demonstrated, which selectively binding to transforming growth factor‐beta (TGF‐β), in which the sensing transduction is enhanced by bound states in the continuum (BICs). The MIP operating as a synthetic antibody matrix and coupled with BIC resonance, enhances the optical response to TGF‐β at imprinted sites, leading to an augmented detection capability, thoroughly evaluated through spectral shift and optical lever analogue readout. The validation underscores the MIP‐BIC sensor capability to detect TGF‐β in spiked saliva, achieving a limit of detection of 10 fM and a resolution of 0.5 pM at physiological concentrations, with a precision of two orders of magnitude above discrimination threshold in patients. The MIP tailored selectivity is highlighted by an imprinting factor of 52, showcasing the sensor resistance to interference from other analytes. The MIP‐BIC sensor architecture streamlines the detection process eliminating the need for complex sandwich immunoassays and demonstrates the potential for high‐precision quantification. This positions the system as a robust tool for biomarker detection, especially in real‐world diagnostic scenarios. [ABSTRACT FROM AUTHOR]

In this study, a novel electrochemiluminescent (ECL) sensor for highly sensitive detection of trilobatin (Tri) was developed based on silver metal–organic frameworks (AgMOFs) and nitrogen-doped carbon quantum dots (N-CDs). N-CDs exhibited high ECL intensity but poor ECL stability, while AgMOFs had a large specific surface area, high porosity, and good adsorption properties. Compositing both of them not only improved the ECL stability of N-CDs, but also enhanced the ECL strength of materials, so AgMOF@N-CD composites were used as the luminophore of the sensor. Under the optimized conditions, the ECL sensor showed a linear range of 1.0 × 10−7 M to 1.0 × 10−3 M for the detection of Tri, and the detection limit was as low as 5.99 × 10−8 M (S/N = 3). In addition, the sensor had excellent reproducibility, stability, and anti-interference ability. It could be utilized for the detection of Tri in real samples with recoveries of 95.78–102.26%, indicating that the constructed ECL sensor for detecting Tri possessed better application prospects. [ABSTRACT FROM AUTHOR]

Glyphosate (GLY) is widely applied in agriculture and horticulture as a herbicide. The development of genetically modified plants has caused abuse of GLY, with excessive residues potentially causing harm to human health. Consequently, a novel method needs to be built to detect GLY in soybeans and corn. Computer simulation was used to design an excellent hapten which was used to produce an anti-GLY monoclonal antibody (mAb) with outstanding sensitivity and affinity, and its 50%-inhibitory concentration (IC50) was 128.59 ng mL−1. Afterwards, an immunochromatographic assay strip was developed based on the mAb. In soybeans and corn, the visual detection limits were 1 mg kg−1 and 0.2 mg kg−1, while the cut-off values were 50 mg kg−1 and 5 mg kg−1, respectively. The reliability of the strips was proved by the existing methods. Thus, a rapid method to detect GLY residues on-site in soybeans and corn was established. [ABSTRACT FROM AUTHOR]

Introduction: Classical Muscovy duck reovirus (C-MDRV) and goose-origin Muscovy duck reovirus (Go-MDRV) infections cause "Liver white-spots disease" in Muscovy duckling and gosling. It is difficult to differentiate the infections caused by C-MDRV and Go-MDRV using conventional serological methods. Methods: Specific primers were designed and synthesized according to σNS and λA nucleotide sequences of C-MDRV and Go-MDRV, respectively. The PCR amplified products were cloned into the pMD-18-T vector. The recombinant plasmid DNA was used to establish an SYBR Green І based duplex real-time PCR assay for the simultaneous detection and differentiation of C-MDRV and Go-MDRV using high-resolution melting (HRM) analysis. The specificity, sensitivity, and repeatability of the methodology were examined based on the optimization of the reaction system and amplification conditions. Results: C-MDRV and Go-MDRV were identified by their distinctive melting temperatures with 84.50 ± 0.25°C for C-MDRV and 87.50 ± 0.20°C for Go-MDRV, respectively. The amplifications were specific, and other non-targeted waterfowl viruses employed in this study did not show normalized melting peaks. The intra- and inter-assay coefficients of variations were between 0.05 and 1.83%, demonstrating good repeatability. The detection limits of this assay were 51.4 copies·μl−1 for C-MDRV and 61.8 copies·μl−1 for Go-MDRV, respectively. A total of 45 clinical samples were tested by RT-qPCR, with positive rates of 15.56% for C-MDRV and 22.22% for Go-MDRV, without co-infections. Discussion: These results suggest that this duplex RT-qPCR method is highly sensitive, specific, and reproducible. The HRM assay established in this study provides a powerful tool for the differential detection and epidemiological investigation of C-MDRV and Go-MDRV. [ABSTRACT FROM AUTHOR]

An optical fiber biosensor based on tapered noncore fiber (NCF) and coupling effect between surface plasmon resonance (SPR) and localized surface plasmon resonance is proposed in this paper. The sensor consists of two multimode fibers and a tapered NCF spliced in the middle. The tapered fiber with a waist diameter of 40 μm is fabricated by flame-heated drawing technology, and then a layer of Au film of 50 nm thickness is deposited on the surface of the taper waist. Au nanoparticles (AuNPs) are immobilized on the surface of the Au film by using the rich functional groups of polydopamine (PDA). The sensitivity is improved by reducing the diameter of the NCF and the electric field coupling between the Au film and AuNPs. The refractive index sensitivity of the sensor is increased to 3558 nm/RIU in the detection range of 1.335–1.365, which is about 1.8 times higher than that of Au-NCF sensor without tapering and AuNPs. Goat anti-rabbit IgG was fixed on the sensor surface through the adhesion effect of PDA and used for the specificity detection of rabbit IgG. The sensitivity and limit of detection (LOD) of the proposed biosensor are 1.16 nm/(μg/ml) and 0.017 μg/ml, respectively. The proposed biosensor has low manufacturing cost and high biological sensitivity, which has potential applications in low concentration biomolecular detection and human health monitoring. [ABSTRACT FROM AUTHOR]

This study evaluates long-read and short-read sequencing for mitochondrial DNA (mtDNA) heteroplasmy detection. 592,315 bootstrapped datasets generated from two single-nucleotide mismatched ultra-deep sequenced mtDNA samples were used to assess basecalling error and accuracy, limit of heteroplasmy detection, and heteroplasmy detection across various coverage depths. Results showed high Phred scores of data with GC-rich sequence bias for long reads. Limit of detection of 12% heteroplasmy was identified, showing strong correlation (R2 ≥ 0.955) with expected heteroplasmy but underreporting tendency of high-level variants. Nanopore sequencing shows potential for direct applicability in mitochondrial diseases diagnostics, but stringent validation processes to ensure diagnostic result quality are required. [ABSTRACT FROM AUTHOR]

Organic optoelectronics have attracted widespread interdisciplinary research interest but lags far behind in the application in marine environmental detection. The organic photoelectrochemical transistor (OPECT) shows promise as a powerful tool for comprehensive monitoring and early warning of marine conditions, which can be further enhanced by the valuable signal amplification strategy of nanozyme‐mediated catalytic precipitation. Herein, OPECT technology is integrated with nanozyme‐mediated catalytic precipitation for the first time, establishing an ultrasensitive detection platform for okadaic acid (OA). Specifically, MXene@MnIn2S4 (MXMnIS) hybrid composed of Schottky‐junction is synthesized via a hydrothermal method, which can efficiently modulate the device with high current gain. Linking with a sandwich immunoassay, the Ru‐C3N4 nanozyme with peroxidase‐mimicking activity can catalyze the oxidation of 4‐chloro‐1‐naphthol (4‐CN) to form an insoluble precipitate on the electrode surface, resulting in a decrease in the photocurrent and altering the transistor response. Importantly, the proposed OPECT biosensor presented an excellent sensitivity and a low detection limit (32.5 pM), fully satisfying the fundamental requirements for the quantitative detection of intracellular and extracellular OA in the practical culture media of Prorocentrum lima at different growth stages. This OPECT platform based on the nanozyme‐mediated quenching effect is significant for effectively monitoring the safety of the marine ecological environment and food safety. [ABSTRACT FROM AUTHOR]

Advanced wireless sensors, incorporating metal‐organic frameworks (MOFs), enzymatic systems, and nanocomposites, offer unparalleled solutions for monitoring analytes and human physiological signals. These cutting‐edge sensors, when used with external devices, enable real‐time monitoring of analytes and physicochemical processes within the human body, thereby enhancing the understanding of complex biological systems. This study presents advancements in sensor development, fabrication techniques, and user‐friendly protocols. The performance of these sensors is evaluated based on their selectivity, sensitivity, and detection limits. Moreover, this article explores limitations, challenges, and key strategies to enhance analyte recognition from onsite environmental and biological species, ensuring human point‐of‐care safety. [ABSTRACT FROM AUTHOR]

Dopamine is an important catecholamine neurotransmitter and its precise determination is of great significance in the diagnosis and treatment of related diseases. This study presents a high‐performance enzyme‐free electrochemical sensor for dopamine determination based on the combination of Prussian blue analogues oxides with multi‐walled carbon nanotubes (PBO@CNTs). The prepared PBO@CNTs exhibited an increased surface area of 49.79 m2/g with abundant mesoporous nanostructure, which providing numerous electroactive sites. Under the optimal conditions, the PBO@CNTs/Au exhibited a high sensitivity of 178.34 μA mM−1 cm−2, a broad linear range between 0.30 μM to 8 mM and a low detection limit of 0.10 μM. It displayed an excellent selectivity towards dopamine by the successive addition of various interfering species through chronoamperometry studies. Besides, the proposed electrodes enjoyed the excellent repeatability, reproducibility and long‐term stability. We also demonstrated the successful application of this sensor for the determination of dopamine in serum. The results indicated that the dopamine‐selective electrochemical enzyme‐free sensors have great potential in clinical application. [ABSTRACT FROM AUTHOR]

Flexible scintillator screens with excellent stability and low detection limits are crucial for X‐ray imaging applications. 0D organic metal halide materials have emerged as a strong contender in the scintillator fields, owing to their excellent optical characteristics and simple maneuverability. Herein, high‐quality and large quantities of C38H36P2Sb2Cl8 single crystals are synthesized through a simple solution approach. The prepared single crystals with dimer‐structure [Sb2Cl8]2− exhibit yellow emission with a near‐unity high photoluminescence quantum yield (PLQY) of 99.8%, and possess an exceptional light yield of 41300 photons MeV−1, and a detection limit as low as 45.6 nGyair s−1. On this basis, a large‐size and ultra‐flexible C38H36P2Sb2Cl8 scintillator utilized for X‐ray imaging is prepared by template assembled method, demonstrating a high spatial resolution of 8.15 lp mm−1. The prepared ultra‐flexible scintillator screen can achieve excellent X‐ray imaging even after multiple bending and stretching, which can also provide clear non‐planar X‐ray imaging for irregular objects. In addition, the scintillator shows excellent stability in light, heat, X‐ray irradiation, and water. These results not only expand the optoelectronic application field of organic‐inorganic hybrid antimony halides but also promote the rapid development of efficient ultra‐flexible scintillators. [ABSTRACT FROM AUTHOR]

Co-infection with novel goose parvovirus (NGPV) and novel duck reovirus (NDRV) is common, significantly impeding duck growth and resulting in considerable economic losses within the duck farming industry. To facilitate rapid and accurate diagnosis and differentiation of these two viruses, this study developed a SYBR Green I-based duplex real-time quantitative polymerase chain reaction (qPCR) assay. This assay enabled the simultaneous detection of NGPV and NDRV by exploiting their distinct melting temperatures (Tm): 78.5 ± 0.50 °C for NGPV and 84.5 ± 0.50 °C for NDRV. No amplification was observed for other prevalent non-target duck viruses. The intra- and inter-assay coefficients of variation were less than 1.75%. The assay showed good performance with the same detection limit of 102 copies/μL for both NGPV and NDRV. The results of the clinical testing indicated that 45.3% (34/75) of the samples tested positive for NGPV, while 38.7% (29/75) were positive for NDRV. Notably, 13.3% (10/75) exhibited co-infection. These results revealed that the sensitivity of the developed method exceed that of conventional polymerase chain reaction (PCR). The developed method for the identifying of NGPV and NDRV shows good specificity, sensitivity, and repeatability, rendering it an effective tool for the simultaneous detection of co-infection with NGPV and NDRV. [ABSTRACT FROM AUTHOR]

Herein, we proposed a novel metal–organic gel (YTU-G-1) for efficient adsorption and portable sensing of gaseous iodine. YTU-G-1 exhibits an unprecedentedly high detection sensitivity (KSV = 2.21 × 106 L mol−1) and an extremely low limit of detection (LOD) down to the pmol level (481 pmol L−1). YTU-G-1 also shows a marked iodine adsorption capacity of 1.398 g g−1. A wearable membrane was successfully fabricated via the electrospinning technique, which exhibits excellent skin-compatibility and serves as a portable tool for sensitive response to potential on-site nuclear emergencies. [ABSTRACT FROM AUTHOR]

Room temperature detection is a crucial objective in semiconductor sensor research, given its inherent benefits including reduced energy consumption, extended sensor lifespan, and significant reduction of safety hazards. Herein, novel room temperature sensing materials, SnO 2 -modified In 2 O 3 porous microrods were synthesized, which exhibited exceptional sensing capability towards formaldehyde at room temperature. Specifically, the 5%-SnO 2 /In 2 O 3 porous microrods demonstrate an impressive sensing response across varying formaldehyde concentrations, even at sub-ppm levels (0.1 ppm, 5.22), with a theoretical detection limit of 5.47 ppb, thereby enabling the detection of trace amounts of formaldehyde. Moreover, the sensors exhibit superior formaldehyde selectivity, rapid response characteristic, as well as good stability and reproducibility. The exceptional formaldehyde sensing ability of the SnO 2 /In 2 O 3 sensor primarily arises from the creation of n-n heterojunctions at the SnO 2 /In 2 O 3 interface, effectively modulating the interfacial potential. Additionally, the presence of SnO 2 enhances the amount of surface-adsorbed oxygen species and active sites, thereby boosting sensing response. The porous rod-like structures further facilitate gas adsorption and diffusion, enhancing gas sensing capabilities. This work presents a novel strategy for constructing SnO 2 -In 2 O 3 heterojunctions to achieve room-temperature formaldehyde detection. [ABSTRACT FROM AUTHOR]

Gallium nitride (GaN)‐on‐Si high electron mobility transistors require insulating GaN buffers, which are prone to charge trapping and result in dynamic ON‐state resistance (dRDS,on) that negatively impacts performance and reliability. Herein, simultaneous measurements of threshold voltage shift (dVTH) and dRDS,on during OFF‐state stress with microsecond time resolution are employed. Ohmic p‐GaN gate contacts enable the use of dVTH to probe charge accumulation under the gate, while dRDS,on probes charge accumulation in the gate‐drain access region. Comparison of dVTH and dRDS,on provides direct evidence of lateral hole transport in the GaN buffer when exposed to a lateral electric field in OFF‐state. This lateral hole transport causes positive charge accumulation in the buffer under the gate and triggers a newly proposed electron injection mechanism into the same region. Only by considering the combination of lateral hole transport and electron injection under the gate the observed up to fivefold dRDS,on increase in OFF‐state stress compared to back‐gating at low biases can be explained. Furthermore, another electron spillover mechanism is introduced that occurs for large positive charge accumulation under the gate and limits the maximum negative dVTH. All known and newly introduced processes during OFF‐state are summarized in a concise dynamic buffer charging model. [ABSTRACT FROM AUTHOR]

Recently, zinc‐based metal halides have attracted numerous attention due to their excellent stability, low toxicity, and wide bandgaps. However, [ZnX4]2− tetrahedra in zinc‐based halides are found to be non‐optically active, which leads to poor photoluminescence quantum yields (PLQYs). Herein, Sb3+ ions are doped into hybrid zinc‐based halides of (C8H26N4)ZnCl6 single crystals (SCs) via an evaporative crystallization method. Compared with undoped (C8H26N4)ZnCl6 SCs with weak blue emission, Sb3+‐doped (C8H26N4)ZnCl6 SCs exhibit a strong broadband emission centered at 694 nm with a high PLQY of 67%, which is confirmed to be derived from self‐trapped excitons (STEs) of Sb3+ luminescent centers. Subsequently, Sb3+‐doped (C8H26N4)ZnCl6 is employed in flexible scintillation films, which demonstrates remarkable X‐ray imaging of complex objects with a spatial resolution of 3.6 lp mm−1 and a detection limit of 123.8 µGyair s−1, proving its promising potential in flexible X‐ray imaging applications. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) transition metal dichalcogenides (TMDs) have recently become attractive candidate substrates for surface-enhanced Raman spectroscopy (SERS) owing to their atomically flat surfaces and adjustable electronic properties. Herein, large-scale 2D 1T′- and 2H-MoTe2 films were prepared using a chemical vapor deposition method. We found that phase structure plays an important role in the enhancement of the SERS performances of MoTe2 films. 1T′-MoTe2 films showed a strong SERS effect with a detection limit of 1 × 10−9 M for the R6G molecule, which is one order of magnitude lower than that of 2H-MoTe2 films. We demonstrated that the SERS sensitivity of MoTe2 films is derived from the efficient photoinduced charge transfer process between MoTe2 and adsorbed molecules. Moreover, a prohibited fish drug could be detected by using 1T′-MoTe2 films as SERS substrates. Our study paves the way to the development and application of high-performance SERS substrates based on TMD phase engineering. [ABSTRACT FROM AUTHOR]

Ascorbic acid (AA) plays an important role in many physiological and biochemical processes. Adequate quantification of AA is required for controlling the intake of AA for health management. In this study, a portable probe was fabricated based on the assembled FePO4@GO nanozyme by homogeneous precipitation. FePO4@GO exhibits excellent peroxidase (POD) activity. As an efficient free radical scavenger, ascorbic acid scavenges 1O2 free radicals produced by hydrogen peroxide catalyzed by peroxidase enzymes and then inhibits the color reaction of 3,3′,5,5′-tetramethylbenzidine (TMB). A good linear relationship between the color of the reaction system and the concentration of AA in the range of 2.5–75 μM was presented, and the detection limit is 1.25 μM. Furthermore, a visual colorimetric detection platform was constructed using a smartphone. The AA content is accurately reflected by intelligent recognition of color changes in the reaction system. It provides an alternative approach for portable and visual rapid detection of Vitamin C (VC) in medicine. Meanwhile, it also provides a reference for the assembly of an intelligent detection platform based on nanozymes. [ABSTRACT FROM AUTHOR]