| 1. |
- Passarelli, Melissa, 1983, et al.
(författare)
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C-60-SIMS studies of glycerophospholipid in a LIPID MAPS model system: KDO2-Lipid A stimulated RAW 264.7 cells
- 2013
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Ingår i: Surface and Interface Analysis. - : Wiley. - 0142-2421 .- 1096-9918. ; 45:1, s. 298-301
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Tidskriftsartikel (refereegranskat)abstract
- Although secondary ion mass spectrometry (SIMS) has been successfully employed for mapping lipid distributions at the cellular level, the identification of intact lipid species in situ is often complicated by isobaric interference. The high mass resolution and tandem MS capabilities of a C60-QSTAR hybrid instrument has been utilized to identify over 50 lipid species from mouse macrophages (RAW 264.7). In this investigation, lipid assignments made based on mass accuracy were confirmed with tandem MS analyses. Data obtained from C60-SIMS was compared to liquid chromatography (LC)-MS data obtained by the LIPID MAPS consortium. A majority of the lipids detected with LC-MS, but not detected with C60-SIMS, were present at concentrations below 2.0 pmol/µg of DNA. Matrix-related effects prevented the detection of lipids with the glycerophosphoethanolamine (PE) headgroup, glycerophosphoserine (PS) headgroup and lipids with polyunsaturated fatty acyl chains in the C60-SIMS analyses. Lipid distributions obtained from a lawn of RAW 264.7 cells stimulated with the endotoxin KDO2-Lipid A were also studied. The results obtained with C60-SIMS agreed with the established LC-MS data for the glycerophosphoinositol lipid class (PI) with adequate molecular sensitivity achieved with as few as 500 cells.
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| 2. |
- Passarelli, Melissa, 1983, et al.
(författare)
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Development of an Organic Lateral Resolution Test Device for Imaging Mass Spectrometry
- 2014
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 86:19, s. 9473-9480
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Tidskriftsartikel (refereegranskat)abstract
- An organic lateral resolution test device has been developed to measure the performance of imaging mass spectrometry (IMS) systems. The device contains periodic gratings of polyethylene glycol (PEG) and lipid bars covering a wide range of spatial frequencies. Microfabrication technologies were employed to produce well-defined chemical interfaces, which allow lateral resolution to be assessed using the edge-spread function (ESF). In addition, the design of the device allows for the direct measurement of the modulation transfer function (MTF) to assess image quality. Scanning electron microscopy (SEM) and time-of-flight secondary ion mass spectrometry (TOF-SIMS) were used to characterize the device. TOF-SIMS imaging was used to measure the chemical displacement of biomolecules in matrix-assisted laser desorption/ionization (MALDI) matrix crystals. In a proof-of-concept experiment, the platform was also used to evaluate MALDI matrix application methods, specifically aerosol spray and sublimation methods.
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| 3. |
- Passarelli, Melissa, 1983, et al.
(författare)
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Single-Cell Lipidomics: Characterizing and Imaging Lipids on the Surface of Individual Aplysia californica Neurons with Cluster Secondary Ion Mass Spectrometry
- 2013
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 85:4, s. 2231-2238
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Tidskriftsartikel (refereegranskat)abstract
- Neurons isolated from Aplysia californica, an organism with a well-defined neural network, were imaged with secondary ion mass spectrometry, C-60-SIMS. A major lipid component of the neuronal membrane was identified as 1-hexadecyl-2-octadecenoyl-sn-glycero-3-phosphocholine [PC(16:0e/18:1)] using tandem mass spectrometry (MS/MS). The assignment was made directly off the sample surface using a C-60-QSTAR instrument, a prototype instrument that combines an ion source with a commercial electrospray ionization/matrix-assisted laser desorption ionization (ESI/MALDI) mass spectrometer, Normal phase liquid chromatography mass spectrometry (NP-LC-MS) was used to confirm the assignment. Cholesterol and vitamin E were also identified with in situ tandem MS analyses that were compared to reference spectra obtained from purified compounds. In order to improve sensitivity on the single-cell level, the tandem MS spectrum of vitamin E reference material was used to extract and compile all the vitamin E related peaks from the cell image. The mass spectrometry images heterogeneous distributions cif intact lipid species, PC(16:0e/18:1), vitamin E, and cholesterol on the surface of a single neuron. The ability to detect these molecules and determine their relative distribution on the single-cell level shows that the C-60-QSTAR is a potential platform for studying important biochemical processes, such as neuron degeneration.
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| 4. |
- Trouillon, Raphaël, 1982, et al.
(författare)
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Chemical Analysis of Single Cells
- 2013
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 85:2, s. 522-542
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Forskningsöversikt (refereegranskat)abstract
- In this Review, we provide an overview of methods developed for chemical analysis of single cells over the last two years. Many biological systems contain an ensemble of cells with heterogeneous chemistry; therefore, it is important to analyze them on an individual basis in order to elucidate the role each cell plays in the function of these systems. In clinical diagnostics, the development of extremely sensitive measurements, down to single cells, may provide the best ability for diagnoses. Single cell analysis has, in fact, been present for quite some time. Investigators in life sciences consider the cell as the unit of life and so the pursuit to quantify, image, and modulate the cell has been ongoing for decades.
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| 5. |
- Yokoyama, Y., et al.
(författare)
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Peptide Fragmentation and Surface Structural Analysis by Means of ToF-SIMS Using Large Cluster Ion Sources
- 2016
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 88:7, s. 3592-3597
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Tidskriftsartikel (refereegranskat)abstract
- Peptide or protein structural analysis is crucial for the evaluation of biochips and biodevices, therefore an analytical technique with the ability to detect and identify protein and peptide species directly from surfaces with high lateral resolution is required. In this report, the efficacy of ToF-SIMS to analyze and identify proteins directly from surfaces is evaluated. Although the physics governing the SIMS bombardment process precludes the ability for researchers to detect intact protein or larger peptides of greater than a few thousand mass unit directly, it is possible to obtain information on the partial structures of peptides or proteins using low energy per atom argon duster ion beams. Large cluster ion beams, such as Ar dusters and C-60 ion beams, produce spectra similar to those generated by tandem MS. The SIMS bombardment process also produces peptide fragment ions not detected by conventional MS/MS techniques. In order to clarify appropriate measurement conditions for peptide structural analysis, peptide fragmentation dependency on the energy of a primary ion beam and ToF-SIMS specific fragment ions are evaluated. It was found that the energy range approximately 6 <= E/n <= 10 eV/atom is most effective for peptide analysis based on peptide fragments and [M + H] ions. We also observed the cleaving of side chain moieties at extremely low-energy E/n <= 4 eV/atom.
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