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Water-assisted laser desorption/ionization mass spectrometry for minimally invasive in vivo and real-time surface analysis using SpiderMass
摘要： Rapid, sensitive, precise and accurate analysis of samples in their native in vivo environment is critical to better decipher physiological and physiopathological mechanisms. SpiderMass is an ambient mass spectrometry (MS) system designed for mobile in vivo and real-time surface analyses of biological tissues. The system uses a fibered laser, which is tuned to excite the most intense vibrational band of water, resulting in a process termed water-assisted laser desorption/ionization (WALDI). The water molecules act as an endogenous matrix in a matrix-assisted laser desorption ionization (MALDI)-like scenario, leading to the desorption/ionization of biomolecules (lipids, metabolites and proteins). The ejected material is transferred to the mass spectrometer through an atmospheric interface and a transfer line that is several meters long. Here, we formulate a three-stage procedure that includes (i) a laser system setup coupled to a Waters Q-TOF or Thermo Fisher Q Exactive mass analyzer, (ii) analysis of specimens and (iii) data processing. We also describe the optimal setup for the analysis of cell cultures, fresh-frozen tissue sections and in vivo experiments on skin. With proper optimization, the system can be used for a variety of different targets and applications. The entire procedure takes 1–2 d for complex samples.
关键词： mass spectrometry,SpiderMass,real-time surface analysis,Water-assisted laser desorption/ionization,in vivo analysis
更新于2025-09-16 10:30:52
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Membrane‐type frizzled‐related protein regulates lipidome and transcription for photoreceptor function
摘要： Molecular decision-makers of photoreceptor (PRC) membrane organization and gene regulation are critical to understanding sight and retinal degenerations that lead to blindness. Using Mfrprd6 mice, which develop PRC degeneration, we uncovered that membrane-type frizzled-related protein (MFRP) participates in docosahexaenoic acid (DHA, 22:6) enrichment in a manner similar to adiponectin receptor 1 (AdipoR1). Untargeted imaging mass spectrometry demonstrates cell-specific reduction of phospholipids containing 22:6 and very long-chain polyunsaturated fatty acids (VLC-PUFAs) in Adipor1?/? and Mfrprd6 retinas. Gene expression of pro-inflammatory signaling pathways is increased and gene-encoding proteins for PRC function decrease in both mutants. Thus, we propose that both proteins are necessary for retinal lipidome membrane organization, visual function, and to the understanding of the early pathology of retinal degenerative diseases.
关键词： RPE cell,retinal degenerations,Adipor1,inflammatory signaling,VLC-PUFAs,matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS)
更新于2025-09-12 10:27:22
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Polyvinylpyrrolidone composite nanofibers as efficient substrates for surface-assisted laser desorption/ionization mass spectrometry
摘要： A matrix-free laser desorption/ionization mass spectrometry (LDI-MS) approach was developed using electrospun composite nanofibers with controllable size, morphology and composition. Composite polyvinylpyrrolidone (PVP) nanofibers with added nanoparticles to enhance the absorption of laser energy absorber were studied. Fractal dimensional analysis was conducted to evaluate the electrospinning process for the first time, which provided useful information on the repeatability of nanofiber production. The performance of the nanofiber-assisted laser desorption/ionization method was investigated through characterization of small drug molecules and synthetic oligomers. Homogeneous sample distribution was achieved by eliminating the “sweet spot”, resulting in good reproducibility. Mass spectra features clean background, that is especially beneficial for interpretation of small molecules. High sensitivity for small drug molecules and synthetic oligomers was obtained with limits of detection limits down to the low attomolar range. The combination of composite nanofibers with LDI-MS is a versatile and sensitive approach for detection and characterization of analytes with broad range of molecular weight.
关键词： Drug molecules,Surface-assisted laser desorption/ionization,Electrospinning,Synthetic polymers,polymeric nanofiber
更新于2025-09-12 10:27:22
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Matrix Assisted Laser Desorption Ionization-Time-of-Flight mass spectrometry identification of <i>Mycobacterium bovis </i>in Bovinae
摘要： In this study, Matrix Assisted Laser Desorption Ionization-Time-of-Flight (MALDI-TOF) mass spectrometry was used to identify Mycobacterium bovis from cattle and buffalo tissue isolates from the North and South regions of Brazil, grown in solid medium and previously identified by Polymerase Chain Reaction (PCR) based on Region of Difference 4 (RD4), sequencing and spoligotyping. For this purpose, the protein extraction protocol and the mass spectra reference database were optimized for the identification of 80 clinical isolates of mycobacteria. As a result of this optimization, it was possible to identify and differentiate M. bovis from other members of the Mycobacterium tuberculosis complex with 100% specificity, 90.91% sensitivity and 91.25% reliability. MALDI-TOF MS methodology described herein provides successful identification of M. bovis within bovine/bubaline clinical samples, demonstrating its usefulness for bovine tuberculosis diagnosis in the future.
关键词： Matrix Assisted Laser Desorption Ionization-Time-of-Flight (MALDI-TOF) mass spectrometry,bovine tuberculosis,Mycobacterium tuberculosis complex,Mycobacterium bovis
更新于2025-09-12 10:27:22
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Comparison of Clusters Produced from Sb2Se3 Homemade Polycrystalline Material, Thin Films, and Commercial Polycrystalline Bulk Using Laser Desorption Ionization with Time of Flight Quadrupole Ion Trap Mass Spectrometry
摘要： This study compared Sb2Se3 material in the form of commercial polycrystalline bulk, sputtered thin film, and homemade polycrystalline material using laser desorption ionization (LDI) time of flight mass spectrometry with quadrupole ion trap mass spectrometry. It also analyzed the stoichiometry of the SbmSen clusters formed. The results showed that homemade Sb2Se3 bulk was more stable compared to thin film; its mass spectra showed the expected cluster formation. The use of materials for surface-assisted LDI (SALDI), i.e., graphene, graphene oxide, and C60, significantly increased the mass spectra intensity. In total, 19 SbmSen clusters were observed. Six novel, high-mass clusters—Sb4Se4+, Sb5Se3-6+, and Sb7Se4+—were observed for the first time when using paraffin as a protective agent.
关键词： Antimony selenide,Clusters,Laser desorption ionization,Paraffin,Chalcogenides
更新于2025-09-11 14:15:04
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Identification and imaging of indole-3-carboxamide cannabinoids in hair using matrix-assisted laser-desorption/ionization mass spectrometry
摘要： Purpose Different kinds of new synthetic cannabinoids (SCs) have been continuously developed to evade drug monitoring. Segmental hair analysis offers a longer period for retrospective drug detection compared with blood or urine. In this study, matrix-assisted laser-desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometric imaging (MALDI-FT ICR MSI) was developed for direct identification and imaging of synthetic indole-3-carboxamide cannabinoids in hair samples using the positive ion mode. Methods The target SCs include N-(adamantan-1-yl)-1-pentyl-1H-indole-3-carboxamide (APICA), N-(1-amino-3-methyl-1-oxobutan-2-yl)-1-(5-fluoropentyl)-1H-indole-3-carboxamide (5F-AB-PICA), N-(1-amino-3,3-dimethyl-1-oxobutan-2-yl)-1-pentyl-1H-indazole-3-carboxamide (ADB-PINACA) and N-(1-amino -3,3-dimethyl-1-oxobutan-2-yl)-1-(5-fluoropentyl)-1H-indole-3-carboxamide (5F-ADBICA). The MALDI-MS and MS/MS were first performed on the scraped hair soaked in a mixture of the four SCs after matrix sublimation. This method may provide a detection power for SCs to the 0.1 ng level per 2 cm hair. Target cannabinoids were identified by MS1 and MS2. Matrix deposition methods including airbrush sprayer and sublimation were compared. Results The method was then applied in revealing the spatial distribution of APICA and 5F-ADBICA in real hair samples from two drug abusers by comparing MS1 and MS2 spectra. The metabolites of APICA and 5F-ADBICA were also presumed to be present in the positive hair samples. Furthermore, a comprehensive comparison between a MALDI-FT ICR MS and a MALDI time-of-flight–MS instrument was performed in detection-sensitivity and specificity for positive real samples. Conclusions The proposed method provides a powerful tool for drug supervision and forensic medicine analysis in a wide time window, and the sample amount required was also decreased.
关键词： Hair analysis,Synthetic cannabinoids,Metabolites,Matrix sublimation,Mass spectrometric imaging,Matrix-assisted laser-desorption/ionization
更新于2025-09-11 14:15:04
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Fe3O4-assisted laser desorption ionization mass spectrometry for typical metabolite analysis and localization: Influencing factors, mechanisms, and environmental applications
摘要： Fe3O4 has been suggested as an efficient matrix for small-molecule analysis by laser desorption ionization mass spectrometry (LDI-MS), but thus far there has been no systematic study exploring the influencing factors of nano-Fe3O4 on the detection of typical metabolites, or the mechanism by which nano-Fe3O4 assists the desorption and ionization of analytes after receiving laser energy. In this study, Fe3O4 nanoparticles with different physicochemical properties were synthesized and characterized. The results revealed that smaller particle size and greater surface hydroxyl amount of nano-spherical Fe3O4 could improve the intensity and relative standard deviation of typical metabolites by LDI-MS. The thermally driven desorption process played a vital role in LDI performance, but the chemical interactions between nano-Fe3O4 and analytes did not. Good intra- or inter-spot repeatability and linearity of analytes were obtained by the optimum Fe3O4-assisted LDI-MS. Finally, the developed method was successfully used for the rapid analysis and localization of endogenous metabolites in biofluids and whole zebrafish tissue section samples. Our results not only elucidate the influencing factors and mechanisms of nano-Fe3O4 for the detection of typical metabolites in LDI-MS but also reveal an innovative tool for the imaging of chemicals in the regions of interest in terms of eco-toxicological research.
关键词： time-of-flight mass spectrometry,physicochemical property,small-molecule metabolite,Fe3O4,laser desorption ionization
更新于2025-09-11 14:15:04
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Satellite-like Gold Nanocomposites for Targeted Mass Spectrometry Imaging of Tumor Tissues
摘要： We have developed a simple, rapid, high-throughput cancer diagnosis system using functional nanoparticles (NPs) consisting of poly(catechin) capped-gold NPs (Au@PC NPs) and smaller nucleolin-binding aptamer (AS1411) conjugated gold NPs (AS1411–Au NPs). The AS1411–Au NPs/Au@PC NP is used as a targeting agent in laser desorption/ionization mass spectrometry (LDI-MS)-based tumor tissue imaging. Self-assembled core-shell Au@PC NPs are synthesized by a simple reaction of tetrachloroaurate(III) with catechin. Au@PC NPs with a well-defined and dense poly(catechin) shell (~40?60 nm) on the surface of each Au core (~60?80 nm) are obtained through careful control of the ratio of catechin to gold ions, as well as the pH of the reaction solution. Furthermore, we have shown that AS1411-conjugated Au NPs (13-nm) self-assembled on Au@PC NP can from a satellite-like gold nanocomposite. The high density of AS1411–Au NPs on the surface of Au@PC NP enhances multivalent binding with nucleolin molecules on tumor cell membranes. We have employed LDI-MS to detect AS1411–Au NPs/Au@PC NPs labeled nucleolin-overexpressing MCF-7 breast cancer cells through the monitoring of Au cluster ions ([Aun]+; 1 ≤ n ≤ 3). The ultrahigh signal amplification from Au NPs through the formation of a huge number of [Aun]+ ions results in a sensing platform with a limit of detection of 100 MCF-7 cells mL?1. Further, we have applied the satellite-like AS1411–Au NPs/Au@PC NP nanocomposite as a labeling agent for tumor tissue imaging by LDI-MS. Our nanocomposite-assisted LDI-MS imaging platform can be extended for simultaneous analysis of different tumor markers on cell membranes when using different ligand-modified metal nanoparticles.
关键词： tissue imaging,aptamers,laser desorption/ionization mass spectrometry,self-assembly,gold nanocomposites
更新于2025-09-04 15:30:14