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Mass spectrometry imaging (MSI) of fresh bones using infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI)
摘要： We report an effective strategy for direct analysis and two-dimensional (2D) infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) mass spectrometry imaging (MSI) of mouse bones that underwent no chemical treatments prior to analysis. To unravel the chemistry in bones under near-physiological conditions, we cut a flash-frozen bone in half longitudinally, placed it in a mold facing flat side down, and poured Plaster of Paris on top of and around the bone. After Plaster of Paris had set, the bone with embedding material was removed from the mold, and placed on the IR-MALDESI imaging stage. Plaster of Paris acted as a fixture to keep every spot on the sample surface the same distance away from the laser focus. To demonstrate the feasibility of IR-MALDESI MSI for analyses of unmodified bones, we imaged bones derived from healthy and stroke-affected mice and generated ion heatmaps showing the spatial distribution of putatively annotated features.
关键词： mouse bones,IR-MALDESI,direct analysis,Plaster of Paris,Mass spectrometry imaging
更新于2025-09-16 10:30:52
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Exfoliated MXene as a mediator for efficient laser desorption/ionization mass spectrometry analysis of various analytes
摘要： The exfoliated MXene (e-MXene) is systematically investigated as a mediator for laser desorption/ionization time-of-flight mass spectrometry (LDI-MS) analysis. Whereas un-exfoliated MXene has no activity for LDI-MS analysis, the e-MXene presents a high resolution, salt-tolerance and efficiency for LDI-MS analysis of various small molecules regardless of their polarity, aromaticity and molecular weight owing to its physicochemical properties such as high laser energy absorption, electrical conductivity and photothermal conversion. Based on our findings, it is clearly confirmed that e-MXene is a promising material for the development of an efficient platform for LDI-MS analysis of small molecules.
关键词： Metabolite,MXene,Mass spectrometry,Laser desorption ionization,Exfoliation
更新于2025-09-16 10:30:52
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Three-Dimensional Imaging of Selenium and Chlorine Distributions in Highly Efficient Selenium-Graded Cadmium Telluride Solar Cells
摘要： Thin-film solar modules based on cadmium telluride (CdTe) technology currently produce the world’s lowest cost solar electricity. However, the best CdTe modules now contain a cadmium selenium telluride (CST) alloy at the front of the absorber layer. Despite this, research characterizing the behavior of selenium in alloyed CdTe devices is currently very limited. Here we employ advanced secondary ion mass spectrometry measurements to map the three-dimensional distribution of selenium in a graded CST/CdTe device for the first time. We find significant interdiffusion of selenium between the CST and CdTe layers in the cell, primarily out of the CST grain boundaries and up into the CdTe grain boundaries and grain fringes above. This results in significant lateral variations in selenium concentrations across grains and hence also lateral fields, which we estimate using the measured selenium concentrations.
关键词： secondary ion mass spectrometry (SIMS),Alloying,CdTe,solar energy
更新于2025-09-16 10:30:52
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Bacterial identification by lipid profiling using liquid atmospheric pressure matrix-assisted laser desorption/ionization mass spectrometry
摘要： Background: In recent years, mass spectrometry (MS) has been applied to clinical microbial biotyping, exploiting the speed of matrix-assisted laser desorption/ionization (MALDI) in recording microbe-specific MS profiles. More recently, liquid atmospheric pressure (AP) MALDI has been shown to produce extremely stable ion flux from homogenous samples and ‘electrospray ionization (ESI)-like’ multiply charged ions for larger biomolecules, whilst maintaining the benefits of traditional MALDI including high tolerance to contaminants, low analyte consumption and rapid analysis. These and other advantages of liquid AP-MALDI MS have been explored in this study to investigate its potential in microbial biotyping. Methods: Genetically diverse bacterial strains were analyzed using liquid AP-MALDI MS, including clinically relevant species such as Escherichia coli, Staphylococcus aureus and Klebsiella pneumoniae. Bacterial cultures were subjected to a simple and fast extraction protocol using ethanol and formic acid. Extracts were spotted with a liquid support matrix (LSM) and analyzed using a Synapt G2-Si mass spectrometer with an in-house built AP-MALDI source. Results: Each species produces a unique lipid profile in the m/z range of 400–1100, allowing species discrimination. Traditional (solid) MALDI MS produced spectra containing a high abundance of matrix-related clusters and an absence of lipid peaks. The MS profiles of the bacterial species tested form distinct clusters using principle component analysis (PCA) with a classification accuracy of 98.63% using a PCA-based prediction model. Conclusions: Liquid AP-MALDI MS profiles can be sufficient to distinguish clinically relevant bacterial pathogens and other bacteria, based on their unique lipid profiles.
关键词： matrix-assisted laser desorption/ionization,mass spectrometry,bacteria,profiling,speciation,MALDI,biotyping,lipids
更新于2025-09-16 10:30:52
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Laser cleavable probes for <i>in situ</i> multiplexed glycan detection by single cell mass spectrometry
摘要： Glycans binding on the cell surface through glycosylation play a key role in controlling various cellular processes, and glycan analysis at a single-cell level is necessary to study cellular heterogeneity and diagnose diseases in the early stage. Herein, we synthesized a series of laser cleavable probes, which could sensitively detect glycans on single cells and tissues by laser desorption ionization mass spectrometry (LDI-MS). This multiplexed and quantitative glycan detection was applied to evaluate the alterations of four types of glycans on breast cancer cells and drug-resistant cancer cells at a single-cell level, indicating that drug resistance may be related to the upregulation of glycan with a b-D-galactoside (Galb) group and Neu5Aca2-6Gal(NAc)-R. Moreover, the glycan spatial distribution in cancerous and paracancerous human tissues was also demonstrated by MS imaging, showing that glycans are overexpressed in cancerous tissues. Therefore, this single-cell MS approach exhibits promise for application in studying glycan functions which are essential for clinical biomarker discovery and diagnosis of related diseases.
关键词： mass spectrometry,breast cancer,drug resistance,laser cleavable probes,single-cell analysis,glycans
更新于2025-09-16 10:30:52
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Protein profiling analysis based on matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometry and its application in typing Streptomyces isolates
摘要： Marine Streptomyces is a potential source of novel bioactive natural products in medicine and agriculture. The current discrimination and screening method of Streptomyces isolates is not accurate and time-consuming, and a novel method is necessary. In this study, a protein profiling method based on an ultrahigh resolution 15 Tesla Matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICR MS) was established and applied for differentiation and bioactivity screening of marine Streptomyces isolates. To obtain robust protein profiling, the effects of the protein extraction method, the matrix-solvent, the sample deposition mode, and the culture time of isolates on protein profiling were thoroughly studied, the optimal conditions were obtained. To evaluate the performance of the developed MALDI-FTICR MS method, MALDI-time of flight (TOF) MS and 16S rRNA were applied in parallel to analyze 25 marine Streptomyces isolates. We found that the clustering result of MALDI-FTICR MS was more similar to that of 16S rRNA than MALDI-TOF MS. And MALDI-FTICR MS could effectively indicate the antibacterial activity of Streptomyces isolates against three plant pathogenic bacteria including Xanthomonas campestris, Xanthomonas oryzae and Erwinia carotovora. Furthermore, a differential protein/peptide was defined and successfully applied to predict antibacterial activity of blind samples. This study demonstrated that MALDI-FTICR MS has great potential to discriminate and screen complex microorganisms, especially those closely related strains.
关键词： Protein profiling,Streptomyces isolates,Cluster analysis,Activity screening,Matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry
更新于2025-09-16 10:30:52
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[IEEE 2019 41st Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC) - Berlin, Germany (2019.7.23-2019.7.27)] 2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Towards OCT-Navigated Tissue Ablation with a Picosecond Infrared Laser (PIRL) and Mass-Spectrometric Analysis
摘要： Medical lasers are commonly used in interventions to ablate tumor tissue. Recently, the picosecond infrared laser has been introduced, which greatly decreases damaging of surrounding healthy tissue. Further, its ablation plume contains intact biomolecules which can be collected and analyzed by mass spectrometry. This allows for a specific characterization of the tissue. For a precise treatment, however, a suitable guidance is needed. Further, spatial information is required if the tissue is to be characterized at different parts in the ablated area. Therefore, we propose a system which employs optical coherence tomography as the guiding imaging modality. We describe a prototypical system which provides automatic ablation of areas defined in the image data. For this purpose, we use a calibration with a robot which drives the laser fiber and collects the arising plume. We demonstrate our system on porcine tissue samples.
关键词： optical coherence tomography,tissue ablation,mass spectrometry,robot calibration,picosecond infrared laser
更新于2025-09-16 10:30:52
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Distribution of Flavan-3-ol Species in Ripe Strawberry Fruit Revealed by Matrix-Assisted Laser Desorption/Ionization-Mass Spectrometry Imaging
摘要： Flavan-3-ols, which comprise proanthocyanidins and their monomers, are major ?avonoids in strawberries, and they have a wide range of biological activities and health bene?ts. However, their spatial distribution in strawberry fruit remains poorly understood. Therefore, we performed matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI), to visualize ? ?avan-3-ols in ripe strawberry fruit. Peaks matching the m/z values of ?avan-3-ols [M ? H] ions were detected in the negative ion mode using 1,5-diaminonaphthalene as matrix. Catechin and/or epicatechin, three B-type procyanidins, and two B-type propelargonidins were identi?ed by MALDI-tandem MS. These ?avan-3-ols were mainly distributed in the calyx, in and around the vascular bundles, and in the skin. In-source fragmentation of proanthocyanidins was determined using their standards, suggesting their distribution was mixed ion images of themselves, and fragment ions generated from those had a higher degree of polymerization. B-type procyanidins were predominantly distributed in the vascular bundles than in the skin, whereas B-type propelargonidins were almost equally distributed between the vascular bundles and skin, suggesting that their distribution patterns are di?erent from the type of their ?avan-3-ol monomers. Flavan-3-ols, especially B-type procyanidins, may help prevent pathogen infection not only in the skin but also in and around the vascular bundles.
关键词： mass spectrometry imaging (MSI),propelargonidins,procyanidins,proanthocyanidins,?avan-3-ols,strawberry,matrix-assisted laser desorption/ionization (MALDI)
更新于2025-09-16 10:30:52
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Performances of ionic liquid matrices with butyl ammonium counterion for matrix-assisted laser desorption/ionization mass spectrometric detection and analysis of sucralfate
摘要： In this work, the performances of two ionic liquid matrices (ILMs) with the same ammonium counterpart for mass spectrometric analysis of the insoluble and soluble sucralfate were compared. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) was performed assisted by the butylammonium salts of a-cyano-hydroxycinnamic acid (CHCAB) and 2,5-dihydroxybenzoic acid (DHBB). CHCAB has a higher IE than DHBB, but better optical properties. CHCAB is more suitable for the analysis of sucralfate, although molecular ions of both compounds were detectable only with low intensities. Thus, optical properties of ILMs are crucial to enhance the sensitivity of MALDI MS detection of polysulfated oligosaccharides.
关键词： sucralfate,a-cyano-hydroxycinnamic acid,Ionic liquid matrices,2,5-dihydroxybenzoic acid,matrix-assisted laser desorption/ionization time-of-flight mass spectrometry
更新于2025-09-16 10:30:52
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Anti-Myocardial Infarction Effects of Radix Aconiti Lateralis Preparata Extracts and Their Influence on Small Molecules in the Heart Using Matrix-Assisted Laser Desorption/Ionization–Mass Spectrometry Imaging
摘要： Radix Aconiti Lateralis Preparata (fuzi) is the processed product of Aconitum carmichaelii Debeaux tuber, and has great potential anti-myocardial infarction e?ects, including improving myocardial damage and energy metabolism in rats. However, the e?ects of Radix Aconiti Lateralis Preparata extracts in a rat model of myocardial infarction have not yet been fully illustrated. Herein, Radix Aconiti Lateral Preparata was used to prepare Radix Aconiti Lateralis Preparata extract (RAE), fuzi polysaccharides (FPS), and fuzi total alkaloid (FTA). Then, we aimed to compare the e?ects of RAE, FPS, and FTA in MI rats and further explore their in?uence on small molecules in the heart. We reported that Radix Aconiti Lateralis Preparata extract (RAE) and fuzi total alkaloid (FTA) signi?cantly improved left ventricular function and structure, and reduced myocardial damage and infarct size in rats with myocardial infarction by the left anterior descending artery ligation. In contrast, fuzi polysaccharides (FPS) was less e?ective than RAE and FTA, indicating that alkaloids might play a major role in the treatment of myocardial infarction. Moreover, via matrix-assisted laser desorption/ionization–mass spectrometry imaging (MALDI–MSI), we further showed that RAE and FTA containing alkaloids as the main common components regulated myocardial energy metabolism-related molecules and phospholipids levels and distribution patterns against myocardial infarction. In particular, it was FTA, not RAE, that could also regulate potassium ions and glutamine to play a cardioprotective role in myocardial infarction, which revealed that an appropriate dose of alkaloids generated more obvious cardiotonic e?ects. These ?ndings together suggested that Radix Aconiti Lateralis Preparata extracts containing an appropriate dose of alkaloids as its main pharmacological active components exerted protective e?ects against myocardial infarction by improving myocardial energy metabolism abnormalities and changing phospholipids levels and distribution patterns to stabilize the cardiomyocyte membrane structure. Thus, RAE and FTA extracted from Radix Aconiti Lateralis Preparata are potential candidates for the treatment of myocardial infarction.
关键词： myocardial infarction,left anterior descending artery ligation,phospholipid,energy metabolism,matrix-assisted laser desorption/ionization–mass spectrometry imaging,Radix Aconiti Lateralis Preparata
更新于2025-09-16 10:30:52