Label-Free Time-of-Flight Secondary Ion Mass Spectrometry Imaging of Sulfur-Producing Enzymes inside Microglia Cells following Exposure to Silver Nanowires.

Autor: Leo BF; Department of Materials and London Centre for Nanotechnology , Imperial College London , Exhibition Road , London SW7 2AZ , U.K.; Central Unit for Advanced Research Imaging (CENTUARI), Faculty of Medicine , University of Malaya , Kuala Lumpur 50603 , Malaysia., Fearn S; Department of Materials and London Centre for Nanotechnology , Imperial College London , Exhibition Road , London SW7 2AZ , U.K., Gonzalez-Cater D; Innovation Center of NanoMedicine , 3 Chome-25-14, Tonomachi , Kawasaki 210-0821 , Japan., Theodorou I; Department of Materials and London Centre for Nanotechnology , Imperial College London , Exhibition Road , London SW7 2AZ , U.K., Ruenraroengsak P; Department of Materials and London Centre for Nanotechnology , Imperial College London , Exhibition Road , London SW7 2AZ , U.K., Goode AE; Department of Materials and London Centre for Nanotechnology , Imperial College London , Exhibition Road , London SW7 2AZ , U.K., McPhail D; Department of Materials and London Centre for Nanotechnology , Imperial College London , Exhibition Road , London SW7 2AZ , U.K., Dexter DT; Innovation Center of NanoMedicine , 3 Chome-25-14, Tonomachi , Kawasaki 210-0821 , Japan., Shaffer M; Department of Materials and London Centre for Nanotechnology , Imperial College London , Exhibition Road , London SW7 2AZ , U.K.; Department of Chemistry and London Centre for Nanotechnology , Imperial College London , Exhibition Road , London SW7 2AZ , U.K., Chung KF; Experimental Studies, National Heart & Lung Institute , Imperial College London , London SW3 6LY , U.K., Porter AE; Department of Materials and London Centre for Nanotechnology , Imperial College London , Exhibition Road , London SW7 2AZ , U.K., Ryan MP; Department of Materials and London Centre for Nanotechnology , Imperial College London , Exhibition Road , London SW7 2AZ , U.K.
Jazyk: angličtina
Zdroj: Analytical chemistry [Anal Chem] 2019 Sep 03; Vol. 91 (17), pp. 11098-11107. Date of Electronic Publication: 2019 Aug 14.
DOI: 10.1021/acs.analchem.9b01704
Abstrakt: There are no methods sensitive enough to detect enzymes within cells, without the use of analyte labeling. Here we show that it is possible to detect protein ion signals of three different H 2 S-synthesizing enzymes inside microglia after pretreatment with silver nanowires (AgNW) using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Protein fragment ions, including the fragment of amino acid (C 4 H 8 N + = 70 amu), fragments of the sulfur-producing cystathionine-containing enzymes, and the Ag + ion signal could be detected without the use of any labels; the cells were mapped using the C 4 H 8 N + amino acid fragment. Scanning electron microscopy imaging and energy-dispersive X-ray chemical analysis showed that the AgNWs were inside the same cells imaged by TOF-SIMS and transformed chemically into crystalline Ag 2 S within cells in which the sulfur-producing proteins were detected. The presence of these sulfur-producing cystathionine-containing enzymes within the cells was confirmed by Western blots and confocal microscopy images of fluorescently labeled antibodies against the sulfur-producing enzymes. Label-free TOF-SIMS is very promising for the label-free identification of H 2 S-contributing enzymes and their cellular localization in biological systems. The technique could in the future be used to identify which of these enzymes are most contributory.
Databáze: MEDLINE
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