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Summary: Phytohormones possess unique chemical structures, and their physiological effects are regulated through intricate interactions or crosstalk among multiple phytohormones. MALDI‐MSI enables the simultaneous detection and imaging of multiple hormones. However, its application for tracing phytohormones is currently restricted by low abundance of hormone in plant and suboptimal matrix selection.2,4‐Dihydroxy‐5‐nitrobenzoic acid (DHNBA) was reported as a new MALDI matrix for the enhanced detection and imaging of multiple phytohormones in plant tissues. DHNBA demonstrates remarkable sensitivity improvement when compared to the commonly used matrix, 2,5‐dihydroxybenzoic acid (DHB), in the detection of isoprenoid cytokinins (trans‐zeatin (tZ), dihy‐drozeatin (DHZ), meta‐topolin (mT), and N6‐(Δ2‐isopentenyl) adenine (iP)), jasmonic acid (JA), abscisic acid (ABA), and 1‐aminocyclo‐propane‐1‐carboxylic acid (ACC) standards.The distinctive properties of DHNBA (i.e. robust UV absorption, uniform matrix deposition, negligible background interference, and high ionization efficiency of phytohormones) make it as an ideal matrix for enhanced detection and imaging of phytohormones, including tZ, DHZ, ABA, indole‐3‐acetic acid (IAA), and ACC, by MALDI‐MSI in various plant tissues, for example germinating seeds, primary/lateral roots, and nodules.Employing DHNBA significantly enhances our capability to concurrently track complex phytohormone biosynthesis pathways while providing precise differentiation of the specific roles played by individual phytohormones within the same category. This will propel forward the comprehensive exploration of phytohormonal functions in plant science. [ABSTRACT FROM AUTHOR]

To achieve the accurate recognition of biomarkers or pathological characteristics within tissues or cells, in situ detection using biosensor technology offers crucial insights into the nature, stage, and progression of diseases, paving the way for enhanced precision in diagnostic approaches and treatment strategies. The implementation of needle-shaped biosensors (N-biosensors) presents a highly promising method for conducting in situ measurements of clinical biomarkers in various organs, such as in the brain or spinal cord. Previous studies have highlighted the excellent performance of different N-biosensor designs in detecting biomarkers from clinical samples in vitro. Recent preclinical in vivo studies have also shown significant progress in the clinical translation of N-biosensor technology for in situ biomarker detection, enabling highly accurate diagnoses for cancer, diabetes, and infectious diseases. This article begins with an overview of current state-of-the-art benchtop N-biosensor designs, discusses their preclinical applications for sensitive diagnoses, and concludes by exploring the challenges and potential avenues for next-generation N-biosensor technology. [ABSTRACT FROM AUTHOR]

The evolution of gas hydrates influenced by the seawater environment is unknown. We present a model of structural transformation from sI hydrate to sII hydrate due to the influence of seawater environment and vent fluid in nature through in situ experiments of gas hydrate formation in the Haima cold seep area. The in situ experimental results indicate that gas hydrates preferentially form as sI hydrates even in cold seep environments where C2+ hydrocarbons are present. During subsequent evolution, the sI hydrates could restructured at the effect of seawater environment and vent fluid, causing transformation to sII hydrates under the influence of hydrate stability. The supply of gas and direct contact with seawater environment are critical factors for structural transformation. Such structural transformation is the result of gas hydrates seeking thermodynamic stability and may be common in active cold seep areas. Plain Language Summary: At high pressures and low temperatures, methane molecules are able to be captured by water in a solid hydrate state, known as natural gas hydrate. The significance of the abundant reserves of natural gas hydrates in the oceans, both in terms of global climate issues and energy resources, has been widely recognised. Since most natural gas reservoirs are dominated by methane (>90%), it is generally accepted that gas hydrates in the oceans tend to be structure I. However, through a field experiment in an active cold seep area, we found that newly generated gas hydrates under the influence of the same cold seep area were of structure I, whereas naturally exposed gas hydrates that had existed for a long period of time on the seafloor were instead of structure II. Based on this, we propose a model of structural transformation (structure I to structure II) of gas hydrates under the influence of seawater environment and vent fluid. This structural transformation may be a natural phenomenon that is common in active cold seep areas. Key Points: In situ experiments have demonstrated that gas hydrates can undergo structural transformation under the influence of seawater environmentNatural structural transformations of gas hydrates are probably common, especially in active cold seep where C2+ hydrocarbons present [ABSTRACT FROM AUTHOR]

The early diagnosis of cancer is vital for effective treatment and improved prognosis. Tumor biomarkers, which can be used for the early diagnosis, treatment, and prognostic evaluation of cancer, have emerged as a topic of intense research interest in recent years. Nucleic acid, as a type of tumor biomarker, contains vital genetic information, which is of great significance for the occurrence and development of cancer. Currently, living cell nucleic acid probes, which enable the in situ imaging and dynamic monitoring of nucleic acids, have become a rapidly developing field. This review focuses on living cell nucleic acid probes that can be used for the early diagnosis of tumors. We describe the fundamental design of the probe in terms of three units and focus on the roles of different nanomaterials in probe delivery. [ABSTRACT FROM AUTHOR]

Water plays a vital role in deteriorating stone heritage, especially those carved into vertical rock slopes. Southeast China is home to numerous limestone rock-hewn heritages, many of which showcase diverse deterioration patterns on their facades. Nevertheless, due to the large scale of this heritage and the limitations imposed by the principle of minimal intervention in practices, there is still a lack of practical strategies for understanding moisture distribution. Therefore, this study aims to analyse the moisture distribution of limestone rock-hewn statues via in situ detection employing a portable hygrometer and laboratory calibration based on the gravimetric method and regression analysis. The in situ determination was conducted in the Ciyunling statues niche 1 (World Heritage Site), which was hewn in the Wuyue states (942 CE). Thirty-six measuring areas were evenly planned on the niche's façade, with 20 moisture readings obtained from each measuring area. Additionally, the surface hardness of the typical area of statues was examined using a non-invasive Leeb hardness tester and Kruskal–Wallis H test to assess the impact of moisture on deterioration. The findings reveal that the statues' moisture content is higher than the background wall between the statues, signalling a greater potential for deterioration on the surface of the limestone statue. The primary source of moisture appears to be gaseous water in the atmosphere, which accumulates in the micropores through capillary condensation. Furthermore, the statistically significant differences in surface hardness between the chest/shoulder of statues and the root of the façade highlight the softening effect of moisture on the foundation of the limestone statues. Hence, the methodology utilised in this study serves as a viable approach for examining moisture levels and the extent of deterioration in rock-hewn heritage structures. Highlights: Systematic in situ measurement of moisture distribution on the facades of limestone rock-hewn heritage. A linear regression equation between limestone's electrical resistance-based moisture content (ωc) and the gravimetric moisture content (ωo) was obtained. The surface of the limestone statues contains more moisture signalling a greater potential for water-induced weathering. the surface hardness of the limestone facade significantly diminishes as the height decreases according to Kruskal–Wallis H test. [ABSTRACT FROM AUTHOR]

Tyrosinase (TYR) emerges as a key enzyme that exerts a regulatory influence on the synthesis of melanin, thereby assuming the role of a critical biomarker for the detection of melanoma. Detecting the authentic concentration of TYR in the skin remains a primary challenge. Distinguished from ex vivo detection methods, this study introduces a novel sensor platform that integrates a microneedle (MN) biosensor with surface-enhanced Raman spectroscopy (SERS) technology for the in situ detection of TYR in human skin. The platform utilized dopamine (DA)-functionalized gold nanoparticles (Au NPs) as the capturing substrate and 4-mercaptophenylboronic acid (4-MPBA)-modified silver nanoparticles (Ag NPs) acting as the SERS probe. Here, the Au NPs were functionalized with mercaptosuccinic acid (MSA) for DA capture. In the presence of TYR, DA immobilized on the MN is preferentially oxidized to dopamine quinone (DQ), a process that results in a decreased density of SERS probes on the platform. TYR concentration was detected through variations in the signal intensity emitted by the phenylboronic acid. The detection system was able to evaluate TYR concentrations within a linear range of 0.05 U/mL to 200 U/mL and showed robust anti-interference capabilities. The proposed platform, integrating MN-based in situ sensing, SERS technology, and TYR responsiveness, holds significant importance for diagnosing cutaneous melanoma. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) are small noncoding RNAs of 18–25 bases. miRNAs are also important new biomarkers that can be used for disease diagnosis in the future. Studies have shown that miR-124 levels are significantly elevated during acute myocardial infarction (AMI) and play a key role in the cardiovascular system. A variety of methods have been established to detect myocardial infarction-related miRNAs. However, most require complex miRNA extraction and isolation, and these methods are virtually undetectable when RNA levels are low in the sample. It may lead to biased results. Thus, it is necessary to develop a technique that can detect miRNA without extracting it, which means that intracellular detection is of great significance. Here, we improved the traditional silicon spheres and obtained a biosensor that could effectively capture and detect specific noncoding nucleic acids through the layer-by-layer assembly method. The sensor is protected by hyaluronic acid so it can successfully escape the lysosome into the cell and achieve detection. With the help of a full-featured microplate reader, we determined that the detection limit of the biosensor could reach 1 fM, meeting the needs of intracellular detection. At the same time, we prepared an oxidative stress cardiomyocyte infarction model and successfully captured the overexpressed miR-124 in the infarcted cells to achieve in situ detection. This study could provide a new potential tool to develop miRNAs for sensitive diagnosis in AMI, and the proposed strategy implies its potential for biomedical research.

Abstract The evolution of gas hydrates influenced by the seawater environment is unknown. We present a model of structural transformation from sI hydrate to sII hydrate due to the influence of seawater environment and vent fluid in nature through in situ experiments of gas hydrate formation in the Haima cold seep area. The in situ experimental results indicate that gas hydrates preferentially form as sI hydrates even in cold seep environments where C2+ hydrocarbons are present. During subsequent evolution, the sI hydrates could restructured at the effect of seawater environment and vent fluid, causing transformation to sII hydrates under the influence of hydrate stability. The supply of gas and direct contact with seawater environment are critical factors for structural transformation. Such structural transformation is the result of gas hydrates seeking thermodynamic stability and may be common in active cold seep areas.

ObjectiveBrassinolide is an important endogenous plant hormone. In this work, an electrochemical immunosensor for in situ detection of brassinolide was constructed using screen-printed electrode (SPE).MethodsAu nanoparticles (AuNPs) were firstly electrodeposited on the surface of SPE electrode by electrochemical workstation, and then CuCl2 nanowires (CuCl2 NWs) were added to the electrode, which can not only increase the conductivity of the electrode, but also Cu2+ can be used as a REDOX probe for the sensor. Finally, Mxene and polydopamine nanocomposite (Mxene@PDA) were selected as the modification materials for SPE electrodes because Mxene has the advantages of large surface area and good electrical conductivity, which can further amplify Cu2+ signals. However, Mxene is easily oxidized and unstable in air. Polydopamine (PDA) contains a large number of catechol and amino groups, which are coated on the surface of Mxene after self-polymerization by dopamine, cutting off the path of oxygen penetration, making Mxene difficult to be oxidized. Mxene@PDA can also be used as a coupling agent to fix more antibodies on the electrode surface, improving the overall biocompatibility, and improve the overall biocompatibility.Results and DiscussionsThe sensor has a wide linear detection range: 0.1 pg/mL to 1 mg/mL, and the detection limit was 0.015 pg/ml (S/N=3). In addition, the content of endogenous brassinolide in wheat was detected by SPE electrodes in vitro and the recovery rate was 98.13% to 104.74%.While verifying the accuracy of the sensor, it also demonstrated its superior stability and sensitivity. Besides, the sensor also showed excellent application potential in the in situ detection of brassinosteroids from wheat leaves. Compared with other brassinolide detection methods, the immunosensor developed in this study has better analytical performance.ConclusionsAn electrochemical immunosensor for in situ detection of brassinolide was developed for the first time, providing a good electrochemical platform for in situ determination of brassinolide in plant leaves, which has great application potential in precision agriculture.

The deep earth, deep sea, and deep space are the main parts of the national “three deep” strategy, which is in the forefront of the strategic deployment clearly defined in China’s 14th Five-Year Plan (2021–2025) and the Long-Range Objectives Through the Year 2035. It is important to reveal the evolutionary process and mechanism of deep tectonics to understand the earth’s past, present and future. The academic connotation of Geology in Time has been given for the first time, which refers to the multi-field evolution response process of geological bodies at different time and spatial scales caused by geological processes inside and outside the Earth. Based on the deep in situ detection space and the unique geological environment of China Jinping Underground Laboratory, the scientific issue of the correlation mechanism and law between deep internal time-varying and shallow geological response is given attention. Innovative research and frontier exploration on deep underground in situ geo-information detection experiments for Geology in Time are designed to be carried out, which will have the potential to explore the driving force of Geology in Time, reveal essential laws of deep earth science, and explore innovative technologies in deep underground engineering.

Semiconductor materials have become a competitive candidate for surface-enhanced Raman scattering (SERS) substrate. However, powdered semiconductors are difficult to execute a fast in situ detection for trace analytes. Here, we developed a new flexible semiconductor SERS substrate by in situ densely growing anatase TiO2 nanoparticles on the surface of cotton fabric through a filtration-hydrothermal method, in which TiO2 exhibits excellent controllability in size and distribution by regulating the ratio of water to alcohol in synthesis and the number of filtration-hydrothermal repetitive cycle. Cotton fabric/TiO2 (Cot/TiO2) substrate exhibits a high SERS activity and excellent spectral repeatability. The developed substrate has an ultra-high stability that can withstand long-term preservation; it can even resist the corrosions of strong acid and alkali, as well as high temperature up to 100 °C and low temperature down to − 20 °C. The flexible substrate can be used to carry out a rapid in situ detection for quinolone antibiotic (enrofloxacin and enoxacin) residues on the fish body surface by using a simple swabbing method, with high quantitative detection potential (up to an order of magnitude of 10−7 M), and even for the simultaneous detection of both drug residues. The flexible substrate also exhibits an excellent recyclability up to 6 recycles in the actual SERS detection. [ABSTRACT FROM AUTHOR]

Wound infections hinder the healing process and potentially result in life-threatening complications, which urgently require rapid and timely detection and treatment pathogens during the early stages of infection. Here, an intelligent wound dressing was developed to enable in situ detection and elimination of pathogenic bacteria through a combination of point-of-care testing and antibacterial photodynamic therapy technology. The dressing is an injectable hydrogel composed of carboxymethyl chitosan and oxidized sodium alginate, with addition of 4-methylumphulone beta-D-glucoside (MUG) and up-converted nanoparticles coated with titanium dioxide (UCNPs@TiO 2). The presence of bacteria can be visually detected by monitoring the blue fluorescence of 4-methylumbellione, generated through the reaction between MUG and the pathogen-associated enzyme. The UCNPs@TiO 2 photosensitizers were synthesized and demonstrated high antibacterial activity through the generation of reactive oxygen species when exposed to near-infrared irradiation. Meanwhile, a smartphone-based portable detection system equipped with a self-developed Android app was constructed for in situ detection of pathogens in mere seconds, detecting as few as 103 colony-forming unit. Additionally, the dressing was tested in a rat infected wound model and showed good antibacterial activity and pro-healing ability. These results suggest that the proposed intelligent wound dressing has potential for use in the diagnosis and management of wound infections. An intelligent wound dressing has been prepared for simultaneous in situ detection and elimination of pathogenic bacteria. The presence of bacteria can be visually detected by tracking the blue fluorescence of the dressing. Moreover, a smartphone-based detection system was constructed to detect and diagnose pathogenic bacteria before reaching the infection limit. Meanwhile, the dressing was able to effectively eliminate key pathogenic bacteria on demand through antibacterial photodynamic therapy under NIR irradiation. The proposed intelligent wound dressing enables timely detection and treatment of infectious pathogens at an early stage, which is beneficial for wound management. [Display omitted] [ABSTRACT FROM AUTHOR]

Liquid biopsy has received increasing attention as a new disease detection modality because of its noninvasive, simple sampling, and reproducible assay advantages. Among the markers of liquid biopsy, extracellular vesicles (EVs) are considered as promising disease biomarkers because they contain a large amount of biological information and have a significant role in physiological activities. The emergence and progression of some of these diseases are associated with miRNAs carried by EVs (EV‐miRNAs). Therefore, high‐sensitive detection of EV‐miRNAs is essential in clinical applications. A growing number of strategies, including biosensors, in situ detection methods, and microfluidics have been developed for the detection of EV‐miRNA and have been applied in the diagnosis of diseases such as cancer. This review summarizes the probes, signal amplification, and detection methods for EV‐miRNA detection, as well as the application of membrane fusion‐based in situ detection and integrated microfluidic chips for EV‐miRNA detection. The challenges of these materials and techniques in clinical diagnostic applications are also discussed. [ABSTRACT FROM AUTHOR]

Abstract Background Pregnant women have an increased risk of getting infected with SARS-CoV-2 and are more prone to severe illness. Data on foetal demise in affected pregnancies and its underlying aetiology is scarce and pathomechanisms remain largely unclear. Case Herein we present the case of a pregnant woman with COVID-19 and intrauterine foetal demise. She had no previous obstetric or gynaecological history, and presented with mild symptoms at 34 + 3 weeks and no signs of foetal distress. At 35 + 6 weeks intrauterine foetal death was diagnosed. In the placental histopathology evaluation, we found inter- and perivillous fibrin depositions including viral particles in areas of degraded placental anatomy without presence of viral entry receptors and SARS-CoV-2 infection of the placenta. Conclusion This case demonstrates that maternal SARS-CoV-2 infection in the third trimester may lead to an unfavourable outcome for the foetus due to placental fibrin deposition in maternal COVID-19 disease possibly via a thrombogenic microenvironment, even when the foetus itself is not infected.

To achieve the accurate recognition of biomarkers or pathological characteristics within tissues or cells, in situ detection using biosensor technology offers crucial insights into the nature, stage, and progression of diseases, paving the way for enhanced precision in diagnostic approaches and treatment strategies. The implementation of needle-shaped biosensors (N-biosensors) presents a highly promising method for conducting in situ measurements of clinical biomarkers in various organs, such as in the brain or spinal cord. Previous studies have highlighted the excellent performance of different N-biosensor designs in detecting biomarkers from clinical samples in vitro. Recent preclinical in vivo studies have also shown significant progress in the clinical translation of N-biosensor technology for in situ biomarker detection, enabling highly accurate diagnoses for cancer, diabetes, and infectious diseases. This article begins with an overview of current state-of-the-art benchtop N-biosensor designs, discusses their preclinical applications for sensitive diagnoses, and concludes by exploring the challenges and potential avenues for next-generation N-biosensor technology.

Water security is an important global issue that is pivotal in the pursuit of sustainable resources for future generations. It is a multifaceted concept that combines water availability with the quality of the water’s chemical, biological, and physical characteristics to ensure its suitability and safety. Water quality is a focal aspect of water security. Quality index data are determined and provided via laboratory testing using expensive instrumentation with high maintenance costs and expertise. Due to increased practices in this sector that can compromise water quality, innovative technologies such as microfluidics are necessary to accelerate the timeline of test procedures. Microfluidic technology demonstrates sophisticated functionality in various applications due to the chip’s miniaturization system that can control the movement of fluids in tiny amounts and be used for onsite testing when integrated with smart applications. This review aims to highlight the basics of microfluidic technology starting from the component system to the properties of the chip’s fabricated materials. The published research on developing microfluidic sensor devices for monitoring chemical and biological contaminants in water is summarized to understand the obstacles and challenges and explore future opportunities for advancement in water quality monitoring.

Liquid biopsy has received increasing attention as a new disease detection modality because of its noninvasive, simple sampling, and reproducible assay advantages. Among the markers of liquid biopsy, extracellular vesicles (EVs) are considered as promising disease biomarkers because they contain a large amount of biological information and have a significant role in physiological activities. The emergence and progression of some of these diseases are associated with miRNAs carried by EVs (EV‐miRNAs). Therefore, high‐sensitive detection of EV‐miRNAs is essential in clinical applications. A growing number of strategies, including biosensors, in situ detection methods, and microfluidics have been developed for the detection of EV‐miRNA and have been applied in the diagnosis of diseases such as cancer. This review summarizes the probes, signal amplification, and detection methods for EV‐miRNA detection, as well as the application of membrane fusion‐based in situ detection and integrated microfluidic chips for EV‐miRNA detection. The challenges of these materials and techniques in clinical diagnostic applications are also discussed.

With ultrafast laser systems reaching presently 10 PW peak power or operating at high repetition rates, research towards ensuring the long-term, trouble-free performance of all laser-exposed optical components is critical. Our work is focused on providing insight into the optical material behavior at fluences below the standardized laser-induced damage threshold (LIDT) value by implementing a simultaneous dual analysis of surface emitted particles using a Langmuir probe (LP) and the target current (TC). ${\mathrm{HfO}}_2$ and ${\mathrm{ZrO}}_2$ thin films deposited on fused silica substrates by pulsed laser deposition at various ${\mathrm{O}}_2$ pressures for defect and stoichiometry control were irradiated by Gaussian, ultrashort laser pulses (800 nm, 10 Hz, 70 fs) in a wide range of fluences. Both TC and LP collected signals were in good agreement with the existing theoretical description of laser–matter interaction at an ultrashort time scale. Our approach for an in situ LIDT monitoring system provides measurable signals for below-threshold irradiation conditions that indicate the endurance limit of the optical surfaces in the single-shot energy scanning mode. The LIDT value extracted from the LP-TC system is in line with the multipulse statistical analysis done with ISO 21254-2:2011(E). The implementation of the LP and TC as on-shot diagnostic tools for optical components will have a significant impact on the reliability of next-generation ultrafast and high-power laser systems.

The low detection sensitivity of lateral-flow immunochromatography assay (LFIA) based on spherical gold nanoparticle (AuNP) limits its wide applications. In the present study, AuNP dimers with strong plasma scattering and robust signal output were synthesized via the Ag ion soldering (AIS) strategy and used as labeled probes in LFIA to boost the sensitivity without any extra operation process and equipment. The established LFIA exhibited high sensitivity with a limit of detection (LOD) of 2.0 × 102 TCID50/mL for PEDV, which provides 50 times higher sensitivity than commercial LFIA based on spherical colloidal gold. In addition, the AuNP dimer–based LFIA showed strong specificity, good reproducibility, high stability, and good accordance to reverse transcription polymer chain reaction (RT-PCR) when detecting 109 clinical samples. Thus, the AuNP dimers is a promising probe for LFIA and the developed AuNP dimer–based LFIA is suitable for the rapid detection of PEDV in the field. [ABSTRACT FROM AUTHOR]

This review aims to elucidate recent developments in electrochemical sensors that use functionalized carbon electrodes with molecularly imprinted polymers (MIPs) for the selective detection of organic compounds in diverse fields including pharmacy, food safety, environmental monitoring of pollutants, and biomedical analysis. The main targets include explosive compounds, dyes, antioxidants, disease biomarkers, pharmaceuticals, antibiotics, allergens, pesticides, and viruses. Following a brief overview of the molecular imprinting principle, the most significant applications are explored. The selection of the functional monomer is subsequently discussed. Notably, various types of carbon electrodes are presented, with a particular emphasis on screen-printed carbon electrodes. The most commonly employed techniques for MIP deposition such as electropolymerization, drop casting, and chemical grafting are introduced and discussed. Electrochemical transduction techniques like cyclic voltammetry, differential pulse voltammetry, square wave voltammetry, and electrochemical impedance spectroscopy are presented. Lastly, the review concludes by examining potential future directions and primary limitations concerning carbon electrodes modified with MIPs. [ABSTRACT FROM AUTHOR]

Background: Pregnant women have an increased risk of getting infected with SARS-CoV-2 and are more prone to severe illness. Data on foetal demise in affected pregnancies and its underlying aetiology is scarce and pathomechanisms remain largely unclear. Case: Herein we present the case of a pregnant woman with COVID-19 and intrauterine foetal demise. She had no previous obstetric or gynaecological history, and presented with mild symptoms at 34 + 3 weeks and no signs of foetal distress. At 35 + 6 weeks intrauterine foetal death was diagnosed. In the placental histopathology evaluation, we found inter- and perivillous fibrin depositions including viral particles in areas of degraded placental anatomy without presence of viral entry receptors and SARS-CoV-2 infection of the placenta. Conclusion: This case demonstrates that maternal SARS-CoV-2 infection in the third trimester may lead to an unfavourable outcome for the foetus due to placental fibrin deposition in maternal COVID-19 disease possibly via a thrombogenic microenvironment, even when the foetus itself is not infected. Novelty: Symptomatic COVID-19 of the mother may cause microthrombotic events in the placenta. These microthrombotic events may lead to placental insufficiency and reduced growth velocity. Further systematic clinical studies investigating the thrombogenic effect of a SARS-CoV-2 infection in pregnancy are warranted. Although a single case report, the findings support previous concerns about placental insufficiency after SARS-CoV-2 infection. This report adds to existing literature and could help support recommendations for additional antenatal testing in similar settings. [ABSTRACT FROM AUTHOR]

Tyrosinase (TYR) emerges as a key enzyme that exerts a regulatory influence on the synthesis of melanin, thereby assuming the role of a critical biomarker for the detection of melanoma. Detecting the authentic concentration of TYR in the skin remains a primary challenge. Distinguished from ex vivo detection methods, this study introduces a novel sensor platform that integrates a microneedle (MN) biosensor with surface-enhanced Raman spectroscopy (SERS) technology for the in situ detection of TYR in human skin. The platform utilized dopamine (DA)-functionalized gold nanoparticles (Au NPs) as the capturing substrate and 4-mercaptophenylboronic acid (4-MPBA)-modified silver nanoparticles (Ag NPs) acting as the SERS probe. Here, the Au NPs were functionalized with mercaptosuccinic acid (MSA) for DA capture. In the presence of TYR, DA immobilized on the MN is preferentially oxidized to dopamine quinone (DQ), a process that results in a decreased density of SERS probes on the platform. TYR concentration was detected through variations in the signal intensity emitted by the phenylboronic acid. The detection system was able to evaluate TYR concentrations within a linear range of 0.05 U/mL to 200 U/mL and showed robust anti-interference capabilities. The proposed platform, integrating MN-based in situ sensing, SERS technology, and TYR responsiveness, holds significant importance for diagnosing cutaneous melanoma.

The detection of polycyclic aromatic hydrocarbons (PAHs) on fruit and vegetable surfaces is important for protecting human health and ensuring food safety. In this study, a method for the in situ detection and identification of PAH residues on fruit and vegetable surfaces was developed using surface-enhanced Raman spectroscopy (SERS) based on a flexible substrate and lightweight deep learning network. The flexible SERS substrate was fabricated by assembling β-cyclodextrin-modified gold nanoparticles (β-CD@AuNPs) on polytetrafluoroethylene (PTFE) film coated with perfluorinated liquid (β-CD@AuNP/PTFE). The concentrations of benzo(a)pyrene (BaP), naphthalene (Nap), and pyrene (Pyr) residues on fruit and vegetable surfaces could be detected at 0.25, 0.5, and 0.25 μg/cm2, respectively, and all the relative standard deviations (RSD) were less than 10%, indicating that the β-CD@AuNP/PTFE exhibited high sensitivity and stability. The lightweight network was then used to construct a classification model for identifying various PAH residues. ShuffleNet obtained the best results with accuracies of 100%, 96.61%, and 97.63% for the training, validation, and prediction datasets, respectively. The proposed method realised the in situ detection and identification of various PAH residues on fruit and vegetables with simplicity, celerity, and sensitivity, demonstrating great potential for the rapid, nondestructive analysis of surface contaminant residues in the food-safety field. [ABSTRACT FROM AUTHOR]

Extracellular vesicles（EVs）are nanoscale vesicles with a phospholipid bilayer structure released by cells through exocytosis under physiological and pathological conditions. EVs, as carriers of information such as proteins, nucleic acids, lipids, and metabolites, can shuttle between cells to play function of material transfer and information exchange, thus they are important for intercellular communication. In recent years, the research of EVs in plant has also been deepening, and there have been great progress in their research and analysis technologies. In this review, we briefly introduce the composition of extracellular vesicles. Then we summarize the current progress in the biological functions of EVs in plants. Furthermore, we analyze the advantages and disadvantages of EV isolation and enrichment methods, as well as the application of EVs in situ imaging technology. Finally, we prospect the potential technologies for the research of plant EVs. [ABSTRACT FROM AUTHOR]

Hydrothermal H2S is an important energy source for hydrothermal ecosystems. However, it is difficult to obtain accurate hydrogen sulfide concentrations in high‐temperature hydrothermal fluids because they are highly susceptible to oxidation and compositional variability with mixing. In this study, a new in situ approach for measuring H2S, HS− and pH in hydrothermal fluids was developed and applied to the detections of Okinawa Trough hydrothermal activities. The in situ total H2S concentrations in the Jade and Biwako fluids were determined to be 31.4 and 76.7 mmol/kg, respectively. The in situ measured pH of the Jade fluids was determined to be 6.3, which has exceeded that of a neutral fluid at a specific temperature and pressure, indicating that the pH of Jade fluids is weakly alkaline. The pH transition of hydrothermal fluids from alkaline to acidic may be attributed to the thermal decomposition of organic matter and sulfide precipitation. Plain Language Summary: Hydrogen sulfide is one of the important gases released from hydrothermal systems, but it is difficult to measure its concentration accurately because it is highly susceptible to oxidation and compositional variability with mixing. The in situ pH of hydrothermal fluids is also a challenging parameter to obtain, as it is significantly affected by factors such as temperature variation and mineral precipitation. Traditional methods of sampling followed by laboratory analysis inevitably result in changes in hydrogen sulfide concentration and pH. Furthermore, conventional chemical sensors and pH electrodes cannot withstand the high‐temperature extreme environment of hydrothermal vents, making it impossible to directly obtain these parameters at the high‐temperature vent orifice. Here, we developed a new method for in situ measurement of the H2S‐HS− ionization equilibrium system based on Raman spectroscopy and used it to determine the H2S concentration and in situ pH of hydrothermal fluids in the Okinawa Trough. Key Points: The first in situ measured pH of high‐temperature hydrothermal vent fluids at arc‐back arc basins was reportedA new approach to obtain in situ H2S/HS− concentration and in situ pH of high temperature hydrothermal vent fluids was establishedThe pH transition of hydrothermal fluids from alkaline to acidic should attributes to the precipitation of sulfide minerals [ABSTRACT FROM AUTHOR]

In geological exploration, it is necessary to analyze the geological history according to the rock types. But in places for people to reach, sample collection, and transportation is a costly task. At present, the remote intelligent detection of rock types needs to be further developed. In this study, laser‐induced breakdown spectroscopy (LIBS), a sensitive optical technique that can rapidly analyze various elements, is applied to real‐time detection and analysis of rock types. Representative rock samples and minerals are selected for spectral analysis and machine learning. The characteristic spectral lines of Ca, Al, Mg, Ti, Si, Na, Fe, K, and Li were observed in the spectra. By comparing the spectra of different samples, the differences among them were discussed. First, principal component analysis (PCA) is used for dimensionality reduction. With the help of PCA, the data are distributed in two‐dimensional and three‐dimensional space and different kinds of rocks and minerals are classified successfully. Then, combined with error back propagation training artificial neural network, the rock and mineral identification model was established, and the recognition rate can reach 100%. The results show that LIBS is a powerful tool for remote intelligent real‐time rock detection and classification, and has great application prospects in the exploration of extraterrestrial objects including planets, satellites and asteroids in the future. [ABSTRACT FROM AUTHOR]

It is important to detect and distinguish different spices because spices are widely used around the world. In this study, wormwood, artemisia annua, lemongrass and clove are taken as examples. First, laser‐induced breakdown spectroscopy (LIBS) is applied to detect and analyze the ash of different spice samples in situ. In the spectra of the ash of different samples, some characteristic lines of metal elements are observed, such as Ca, Na, Mg, K, and so on. By comparing the spectra of the ash, the relative intensities of the characteristic peaks are different, which can be employed to identify and distinguish different spice samples. Then, using LIBS combined with principal component analysis (PCA) and error back propagation artificial neural network (BP‐ANN), the model of classification is established to distinguish different spices. In PCA, the dimension of the spectra of the ash is reduced, and the cumulative contribution rate of the first two PCs exceeds 90%. The samples after dimension reduction by PCA are classified by BP‐ANN, and the recognition rate can reach 100%. After 10 cross‐verifications, the final recognition accuracy can reach 85.25%. All of the results show the model of classification has the potential in the field of identification and distinction of different spices. [ABSTRACT FROM AUTHOR]

Benzylisoquinoline alkaloids in lotus (Nelumbo nucifera) seed plumules and leaves exhibit significant tissue specificity for their pharmacological effects and potential nutritional properties. Herein, 46 benzylisoquinoline alkaloids were identified via UPLC-QTOF-HRMS, of which 9 were annotated as glycosylated monobenzylisoquinoline alkaloids concentrated in the seed plumules. The spatial distribution of targeted benzylisoquinoline alkaloids in leaves, seed plumules, and milky sap was determined via MALDI–MSI. Furthermore, 37 Nelumbo cultivars were investigated using targeted metabolomics to provide insights into functional tea development. While aporphine alkaloids comprised the main compounds present in lotus leaves, bisbenzylisoquinoline alkaloids were the main compounds in lotus plumules, where glycosylation primarily occurs. These findings can help understand the distribution of benzylisoquinoline alkaloids in lotus tissue and the directional breeding of varieties enriched with specific chemical functional groups for nutritional and pharmacological applications.

Abstract Hydrothermal H2S is an important energy source for hydrothermal ecosystems. However, it is difficult to obtain accurate hydrogen sulfide concentrations in high‐temperature hydrothermal fluids because they are highly susceptible to oxidation and compositional variability with mixing. In this study, a new in situ approach for measuring H2S, HS− and pH in hydrothermal fluids was developed and applied to the detections of Okinawa Trough hydrothermal activities. The in situ total H2S concentrations in the Jade and Biwako fluids were determined to be 31.4 and 76.7 mmol/kg, respectively. The in situ measured pH of the Jade fluids was determined to be 6.3, which has exceeded that of a neutral fluid at a specific temperature and pressure, indicating that the pH of Jade fluids is weakly alkaline. The pH transition of hydrothermal fluids from alkaline to acidic may be attributed to the thermal decomposition of organic matter and sulfide precipitation.

Oral processing is a combination of various actions, the detailed description of which has always been the subject of relevant research. By means of imaging technology and sensory evaluation, more knowledge of oral processing have been accumulated. Presently, the advances in sensory technology have added quantitative parameters to the qualitative description of oral processing, which also enriched the specifics of each action. Previous studies have shown that oral processing includes lip closure, dental occlusion, masticatory muscles activity, tongue movement, and swallowing, whose processing contains rich information such as the movement of organ and the intensity of organ contacts. "Quantification" was taken in this review as the basic feature of in situ detection information, the relevant parameters and feasible methods for the quantitative description of each activity was recorded in detail. In addition, basic problems and feasible optimization schemes of the existing in situ detection device are also proposed in the hope of promoting the development of in situ detection device thus providing available information for the description of oral processing. [ABSTRACT FROM AUTHOR]

Large-scale, high-density geochemical explorations entail enormous workloads and high costs for sample analysis, but, for early mineral exploration, absolute concentrations are not essential. Geochemists require ranges, dynamics of variation, and correlations for early explorations rather than absolute accuracy. Thus, higher work efficiency and lower costs for sample analysis are desirable for geochemical exploration. This study comprehensively analyzed the reliability and applicability of portable X-ray fluorescence (pXRF) spectrometry in geochemical exploration. The results show that pXRF can be applied effectively to rock and rock powder samples, and sample preparation and a longer detection time have been shown to increase the precision of the pXRF results. When pXRF is used on rock samples, if less than 30% of the samples are assessed as containing an element, the element is usually undetectable using pXRF when these rock samples are prepared as rock powders, indicating that the data about the detected element are unreliable; thus, it is suggested that some representative samples should be selected for testing before starting to use a pXRF in a geochemical exploration project. In addition, although the extended detection time increased the reliability of the analysis results, an increase in detection time of more than 80 s did not significantly affect the accuracy of the results. For this reason, the recommended detection time for the pXRF analysis of rock powder samples is 80 s for this study. pXRF has the advantages of being low-cost, highly efficient, and stable, and its results are reliable enough to exhibit the spatial distribution of indicator elements (arsenic, nickel, lead, sulfur, titanium, and zinc) in polymetallic mineralization exploration. Therefore, pXRF is recommendable for practical use in geochemical exploration. [ABSTRACT FROM AUTHOR]

There are an increasing number of experiments to study programmed cell death/apoptosis, one of the characteristics of which is DNA fragmentation. The only current method for in situ detection of DNA fragmentation is Terminal deoxynucleotidyl transferase mediated-dUTP Nick End Labeling, TUNEL. In this study, a new method for in situ detection of apoptotic DNA fragments, namely In Situ Hybridization Chain Reaction, isHCR, was established. The principle of the assay is that the sticky end sequence of the apoptotic cell DNA fragment non-specifically initiates a hybridization chain reaction that specifically detects the apoptotic cell. The results of the combined TUNEL and isHCR method demonstrated that the majority of isHCR-positive cells were also labeled by TUNEL. In situ HCR often detect DNA fragments in the cytoplasm that the classical TUNEL method couldnot, and these cells may be in the early stages of apoptosis. It also indicates that DNA fragments are transferred to the cytoplasm during apoptosis. Because the staining process does not require terminal deoxynucleotidyl transferase as TUNEL staining does, isHCR staining cost low and can be performed on a large number of tissue specimens. It is believed that isHCR has the potential to detect DNA fragmentation of apoptotic cells in situ. [ABSTRACT FROM AUTHOR]

Microstructure fibers, integrating microfluidic channels and light guidance in one fiber, enable three-dimensional surface-enhanced Raman scattering (SERS) detection for large signal accumulation. However, the available fiber SERS probes are complicated to prepare and they are not reusable. In addition, light interacts with analytes in a form of an evanescent field, which is very weak. In this paper, we developed a SERS platform based on suspended-core photonic crystal fibers decorated with Ag/ZnO nanocomposites on the inner surface for direct, ultrasensitive, and reusable analyte detection. The unique configuration not only transfers a core-localized field to the liquid interface to greatly enhance the light–analyte interaction but also facilitates charge transfer to further improve the SERS detection sensitivity and degradation efficiency. The detection limit of crystal violet solution is 10–13 M, and the enhancement factor reaches 1011. The relative standard deviation is as low as 5.4%, ensuring the reproducibility of SERS detection. The probe has good photocatalytic performance and can degrade molecules under ultraviolet-light illumination within 20 min. This ultrasensitive and reusable SERS probe shows great application potential in rapid and in situ liquid detection. [ABSTRACT FROM AUTHOR]

Summary: Detecting the simultaneous presence of a microRNA (miRNA) and a mRNA in a specific tissue can provide support for the prediction that the miRNA regulates the mRNA. Although two such methods have been developed for mammalian tissues, they have a low signal‐noise ratio and/or poor resolution at the single‐cell level. To overcome these drawbacks, we develop a method that uses sequence‐specific miRNA‐locked nucleic acid (LNA) and mRNA‐LNA probes. Moreover, it augments the detection signal by rolling circle amplification, achieving a high signal‐noise ratio at the single‐cell level. Dot signals are counted for determining the expression levels of mRNA and miRNA molecules in specific cells. We show a high sequence specificity of our miRNA‐LNA probe, revealing that it can discriminate single‐base mismatches. Numerical quantification by our method is tested in transgenic rice lines with different gene expression levels. We conduct several applications. First, the spatial expression profiling of osa‐miR156 and OsSPL12 in rice leaves reveals their specific expression in mesophyll cells. Second, studying rice and its mutant lines with our method reveals opposite expression patterns of miRNA and its target mRNA in tissues. Third, the dynamic expression profiles of ZmGRF8 and zma‐miR396 during maize leaf development provide evidence that zma‐miR396 regulates the preferential spatial expression of ZmGRF8 in bundle sheath cells. Finally, our method can be scaled up to simultaneously detect multiple miRNAs and mRNAs in a tissue. Thus, it is a sensitive and versatile technique for studying miRNA regulation of plant tissue development. [ABSTRACT FROM AUTHOR]

Exosomes are considered as biomarkers reflecting the physiological state of the human body. Studies have revealed that the expression levels of specific exosomal RNAs are closely associated with certain cancers. Thus, detection of exosomal RNA offers a new avenue for liquid biopsy of cancers. Many exosomal RNA detection methods based on various principles have been developed, and most of the methods detect the extracted RNAs after lysing exosomes. Besides complex and time-consuming extraction steps, a major drawback of this approach is the degradation of the extracted RNAs in the absence of plasma membrane and cytosol. In addition, there is considerable loss of RNAs during their extraction. In situ detection of exosomal RNAs can avoid these drawbacks, thus allowing higher diagnostic reliability. In this paper, in situ detection of exosomal RNAs was systematically reviewed from the perspectives of detection methods, transport methods of the probe systems, probe structures, signal amplification strategies, and involved functional materials. Furthermore, the limitations and possible improvements of the current in situ detection methods for exosomal RNAs towards the clinical diagnostic application are discussed. This review aims to provide a valuable reference for the development of in situ exosomal RNA detection strategies for non-invasive diagnosis of cancers. Certain RNAs have been identified as valuable biomarkers for some cancers, and sensitive detection of cancer-related RNAs is expected to achieve better diagnostic efficacy. Currently, the detection of exosomal RNAs is receiving increasing attention due to their high stability and significant concentration differences between patients and healthy individuals. In situ detection of exosomal RNAs has greater diagnostic reliability due to the avoidance of RNA degradation and loss. However, this mode is still limited by some factors such as detection methods, transport methods of the probe systems, probe structures, signal amplification strategies, etc. This review focuses on the progress of in situ detection of exosomal RNAs and aims to promote the development of this field. [Display omitted] [ABSTRACT FROM AUTHOR]

PIWI-interacting RNAs (piRNAs) are a novel class of non-coding RNAs that bind specifically to the PIWI subfamily of Argonaut proteins. It has been increasingly demonstrated that piRNAs encased in circulating exosomes could be an ample source of potential tumor markers for cancer diagnostics. However, methods on exosomal piRNAs detections are limited, and most of them need extraction of piRNAs from the sample which is laborious and disadvantage to clinical applications. Herein, we developed two kinds of dual-targeted spherical nucleic acid nanoprobes for in situ and multiplex detection of exosomal piRNAs. The detection scheme was rationally designed for the large sized targets of PIWI-interacting RNA complex which could generate steric hindrance in the detection reaction. The probes were synthesized by modifying 13-nm gold particles with high-density double stranded anchor-report DNA through butanol dehydration method. The key synthesis condition of molar ratio between the two kinds of anchor-report DNA chains were optimized for preparing probes with good structural reproducibility. The probes can perform in situ and multiplex detection of piRNAs in exosomes after simple incubation. In the clinical assays of plasma from breast cancer patients and normal control groups, the probes can differentiate the expression levels of 3 types of piRNAs and their combinations in high specificity and sensitivity. These new piRNA probes are potentially to perform simple and accurate liquid biopsy for cancer diagnostics. • The sensors have new structures for detecting large PIWI-interacting RNA complexes. • The key reaction condition for synthesis of the sensors was found. • The sensors can in situ detect multiple types of piRNAs encased in exosomes. • The breast cancer plasma biopsy based on the sensors achieved high accuracy. [ABSTRACT FROM AUTHOR]

As a commonly used food additive, excessive nitrite intake seriously affects people's health in daily life. As the stomach is the main organ involved in nitrite intake, achieving fast and in situ detection of nitrite in the stomach is of great significance for avoiding the hazards caused by nitrite. However, owing to the poor stability or low sensitivity of existing fluorescent probes under acidic conditions, their application for nitrite detection within the stomach remains challenging. To solve this problem, we developed novel probes specifically designed to maintain stability and demonstrate high sensitivity to nitrite under acidic conditions. Utilizing the optimized probe (DHUROS-11), nitrite levels in environmental and real samples were successfully quantified. Notably, tracing of nitrite within the stomach of mice in real time was realized by using DHUROS-11 as the probe. [Display omitted] • Fluorescent probes high sensitive to nitrite under acid conditions are developed. • It provides a paradigm for the construction of novel nitrite fluorescent probes. • The probes can quantify nitrite levels in environmental and real samples. • Using the selected probe, nitrite in the stomach is detected in situ. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel methodology is created to detect and identify petroleum polluted soils. • LIBS and self-improved machine learning were firstly used to study PHC pollution. • Quantitative analysis of concentration of petroleum in soils was done accurately. • Volatile component of the PHC polluted soils was successfully detected and identified. Petroleum hydrocarbon (PHC) contamination in soils is considered one of the most serious problems currently, of which the detection and identification is a fairly significant but challenging work. Conventional methods to do such work usually need complex sample pretreatment, consume much time and fail to do the in-situ detection. This paper set out to create a novel systematic methodology to realize the goals accurately and efficiently. Based on laser-induced breakdown spectroscopy (LIBS) and self-improved machine learning methods, the innovative methodology only uses extremely simple devices to do the real-time in situ detection and identification work and even realize the quantitative analysis of pollution level accurately. In the study, clean soils mixed with petroleum were served as polluted samples, clean soils to be the blank group for comparison. Based on the elemental information from the spectra obtained by LIBS, machine learning methods were improved and helped optimized the algorithm to identify the PHC polluted soil samples for the first time. Furthermore, a novel model was designed to perform the quantitative analysis of the concentration of PHC pollution in soils, which can be applied to detect the degree of PHC contamination in soils accurately. Finally, the harmful volatile component of the PHC polluted soils was also successfully and identified despite its extremely minimal content in the air. The newly-designed methodology is novel and efficient, which has extensive application prospect in the real-time in situ detection of petroleum hydrocarbon pollution. [ABSTRACT FROM AUTHOR]

Conventional ex situ analytical methods for sediment pore water are susceptible to disruptions in the speciation equilibrium of metals due to changes in external conditions. This study introduced an innovative in situ method for detecting the three-dimensional distribution of labile copper (Cu Labile) in sediment pore water with high spatial resolution using a highly stable microneedle electrochemical sensor. The sensor featured a nanoporous tip structure and embedded gold nanomaterials with excellent electrocatalytic performance. The nanoporous structure could prevent the nanomaterials from falling off because of friction during the in situ detection process in sediments. The sensor exhibited good detection performance under different salinity conditions with a detection limit of 0.2 nM. Vertical and three-dimensional distributions of Cu Labile in sediment pore water were successfully obtained using the in situ microneedle sensor. The results showed that the concentration of Cu Labile was in the range of 5.2–43.5 nM, with a maximum value at a depth of approximately 4 cm, while there was almost no difference in the horizontal direction of a specific sediment sample column. Furthermore, this functional sensor could be extended to the in situ detection of other labile metals in sediment pore water. [Display omitted] • A functional microneedle sensor with nanoporous tip structure was fabricated. • The tip nanopores of the microneedle sensor were embedded with gold nanoparticles. • The method for in situ detection of labile Cu with the sensor was established. • In situ detection of labile Cu in sediment pore water was achieved with the sensor. • The vertical and 3D distribution of labile Cu in sediment pore water was obtained. [ABSTRACT FROM AUTHOR]

This review aims to elucidate recent developments in electrochemical sensors that use functionalized carbon electrodes with molecularly imprinted polymers (MIPs) for the selective detection of organic compounds in diverse fields including pharmacy, food safety, environmental monitoring of pollutants, and biomedical analysis. The main targets include explosive compounds, dyes, antioxidants, disease biomarkers, pharmaceuticals, antibiotics, allergens, pesticides, and viruses. Following a brief overview of the molecular imprinting principle, the most significant applications are explored. The selection of the functional monomer is subsequently discussed. Notably, various types of carbon electrodes are presented, with a particular emphasis on screen-printed carbon electrodes. The most commonly employed techniques for MIP deposition such as electropolymerization, drop casting, and chemical grafting are introduced and discussed. Electrochemical transduction techniques like cyclic voltammetry, differential pulse voltammetry, square wave voltammetry, and electrochemical impedance spectroscopy are presented. Lastly, the review concludes by examining potential future directions and primary limitations concerning carbon electrodes modified with MIPs.

Volatile compounds such as ethanol released from fruit can be rapidly detected using Fourier Transform Infrared spectroscopy based on a long-path gas cell. However, this method relies on a long optical path length and requires pumping fruit volatiles into the gas cell. This can lead to the volatile compounds being contaminated and not detectable in situ. Fiber optic evanescent wave spectroscopy (FOEW) is not influenced by the path length so can detect materials (solid, liquid and gas phase) rapidly in situ, using only a few millimeters of optical fiber. In the present study, a spiral silver halide FOEW sensor with a length of approximately 21 mm was used to replace a long-path gas cell to explore the feasibility of identifying volatile compounds released from grapes in situ. The absorption peaks of ethanol in the volatile compounds were clearly found in the FOEW spectra and their intensity gradually increased as the storage time of the grapes increased. PCA analysis of these spectra showed clear clustering at different storage times (1-3, 4-5 and 6-7 d), revealing that the concentration of the ethanol released from the grapes changed significantly with time. The qualitative model established by PLS-DA algorithm could accurately classify grape samples as “Fresh,” “Slight spoilage,” or “Severe spoilage”. The accuracy of the calibration and validation sets both were 100.00%. These changes can therefore be used for rapidly identifying fruit deterioration. Compared with the method used in a previous study by the authors, this method avoids using a pumping process and can thus identify volatile compounds and hence monitor deterioration in situ and on-line by placing a very short optical fiber near the fruit. [ABSTRACT FROM AUTHOR]

Direct in situ imaging of nucleic acids on biological samples is advantageous for rapid analysis without DNA extraction. However, traditional nucleic acid amplification in aqueous solutions tends to lose spatial information because of the high mobility of molecules. Similar to a cellular matrix, hydrogels with biomimetic 3D nanoconfined spaces can limit the free diffusion of nucleic acids, thereby allowing for ultrafast in situ enzymatic reactions. In this study, hydrogel-based in situ space-confined interfacial amplification (iSCIA) is developed for direct imaging of single nucleic acid and single pathogen on biological samples without formaldehyde fixation. With a polyethylene glycol hydrogel coating, nucleic acids on the sample are nanoconfined with restricted movement, while in situ amplification can be successfully performed. As a result, the nucleic acids are lighted-up on the large-scale surface in 20 min, with a detection limit as low as 1 copy/10 cm 2 . Multiplex imaging with a deep learning model is also established to automatically analyze multiple targets. Furthermore, the iSCIA imaging of pathogens on plant leaves and food is successfully used to monitor plant health and food safety. The proposed technique, a rapid and flexible system for in situ imaging, has great potential for food, environmental, and clinical applications., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Plant hormones are essential and structurally diverse molecules that regulate various aspects of plant growth, development, and stress responses. However, the precise analysis of plant hormones in complex biological samples poses a challenge due to their low concentrations, dynamic levels, and intricate spatial distribution. Moreover, the complexity and interconnectedness of hormone signaling networks make it difficult to simultaneously trace multiple hormone distributions. In this review, we provide an overview of the currently recognized small-molecule plant hormones, signal peptide hormones, and plant growth regulators, along with the analytical methods employed for their analysis. We delve into the latest advancements in mass spectrometry imaging and in situ fluorescence techniques, which enable the examination of the spatial distribution of plant hormones. The advantages and disadvantages of these imaging techniques are further discussed. Finally, we propose potential avenues for future research in this field to further enhance our understanding of plant hormone biology., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Volatile compounds such as ethanol released from fruit can be rapidly detected using Fourier Transform Infrared spectroscopy based on a long-path gas cell. However, this method relies on a long optical path length and requires pumping fruit volatiles into the gas cell. This can lead to the volatile compounds being contaminated and not detectable in situ. Fiber optic evanescent wave spectroscopy (FOEW) is not influenced by the path length so can detect materials (solid, liquid and gas phase) rapidly in situ, using only a few millimeters of optical fiber. In the present study, a spiral silver halide FOEW sensor with a length of approximately 21 mm was used to replace a long-path gas cell to explore the feasibility of identifying volatile compounds released from grapes in situ. The absorption peaks of ethanol in the volatile compounds were clearly found in the FOEW spectra and their intensity gradually increased as the storage time of the grapes increased. PCA analysis of these spectra showed clear clustering at different storage times (1-3, 4-5 and 6-7 d), revealing that the concentration of the ethanol released from the grapes changed significantly with time. The qualitative model established by PLS-DA algorithm could accurately classify grape samples as “Fresh,” “Slight spoilage,” or “Severe spoilage”. The accuracy of the calibration and validation sets both were 100.00%. These changes can therefore be used for rapidly identifying fruit deterioration. Compared with the method used in a previous study by the authors, this method avoids using a pumping process and can thus identify volatile compounds and hence monitor deterioration in situ and on-line by placing a very short optical fiber near the fruit.

The detection of polycyclic aromatic hydrocarbons (PAHs) on fruit and vegetable surfaces is important for protecting human health and ensuring food safety. In this study, a method for the in situ detection and identification of PAH residues on fruit and vegetable surfaces was developed using surface-enhanced Raman spectroscopy (SERS) based on a flexible substrate and lightweight deep learning network. The flexible SERS substrate was fabricated by assembling β-cyclodextrin-modified gold nanoparticles (β-CD@AuNPs) on polytetrafluoroethylene (PTFE) film coated with perfluorinated liquid (β-CD@AuNP/PTFE). The concentrations of benzo(a)pyrene (BaP), naphthalene (Nap), and pyrene (Pyr) residues on fruit and vegetable surfaces could be detected at 0.25, 0.5, and 0.25 μg/cm2, respectively, and all the relative standard deviations (RSD) were less than 10%, indicating that the β-CD@AuNP/PTFE exhibited high sensitivity and stability. The lightweight network was then used to construct a classification model for identifying various PAH residues. ShuffleNet obtained the best results with accuracies of 100%, 96.61%, and 97.63% for the training, validation, and prediction datasets, respectively. The proposed method realised the in situ detection and identification of various PAH residues on fruit and vegetables with simplicity, celerity, and sensitivity, demonstrating great potential for the rapid, nondestructive analysis of surface contaminant residues in the food-safety field.

Spatter is an inherent, unpreventable, and undesired phenomenon in laser powder bed fusion (L-PBF) additive manufacturing. Spatter behavior has an intrinsic correlation with the forming quality in L-PBF because it leads to metallurgical defects and the degradation of mechanical properties. This impact becomes more severe in the fabrication of large-sized parts during the multi-laser L-PBF process. Therefore, investigations of spatter generation and countermeasures have become more urgent. Although much research has provided insights into the melt pool, microstructure, and mechanical property, reviews of spatter in L-PBF are still limited. This work reviews the literature on the in situ detection, generation, effects, and countermeasures of spatter in L-PBF. It is expected to pave the way towards a novel generation of highly efficient and intelligent L-PBF systems. [ABSTRACT FROM AUTHOR]

The extreme environment of the deep sea has shaped special life processes with great resource potential, and its detection and research are the frontier of international earth science. While the harsh high-pressure environment of the deep sea greatly limits the application of deep-sea sampling and detection technology, the deep-sea in situ detection technology can obtain the component and content information of deep-sea samples without changing the location and state of the measured object, hence it is more and more widely used in the research of deep-sea extreme environment. The deep-sea extreme environment in situ detection technology has a broad prospect. However, as an emerging detection technology, many scientific problems still need to be solved. This study summarizes the international and domestic research progress of deep-sea extreme environment in situ detection technology, and puts forward the future development strategies for the research of deep-sea extreme environment in situ detection technology in China. [ABSTRACT FROM AUTHOR]