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Jenčič B, Pongrac P, Vasić M, Starič P, Kelemen M, Regvar M. Gold-Assisted Molecular Imaging of Organic Tissue by MeV Secondary Ion Mass Spectrometry. J Am Soc Mass Spectrom 2023; 34:2358-2364. [PMID: 37682634 PMCID: PMC10557134 DOI: 10.1021/jasms.3c00237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/12/2023] [Accepted: 08/30/2023] [Indexed: 09/10/2023]
Abstract
The quality of molecular imaging by means of MeV primary ion-induced secondary ion mass spectrometry by coating with gold was evaluated on different reference organic molecules and plant samples. The enhancement of the secondary ion yield was evident for the majority of the studied analytes, reaching the highest values at gold thicknesses between 0.5 and 2 nm, and increased the intensity up to 5-fold for reference samples and >2-fold for specific peaks within the plant sample. Improved propagation of the electric field due to the target potential on otherwise electrically insulating plant samples was also evident through improved image resolution and by reducing the background in mass spectra. However, detection of several molecules was significantly decreased at even at 1 nm thick gold layer. The results indicated that an optimized sequence of analysis is required to reliably interpret results.
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Affiliation(s)
- Boštjan Jenčič
- Jožef
Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - Paula Pongrac
- Jožef
Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
- Biotechnical
Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia
| | - Mirjana Vasić
- Jožef
Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
- Jožef
Stefan Institute Postgraduate School, Jamova 39, 1000 Ljubljana, Slovenia
| | - Pia Starič
- Jožef
Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
- Biotechnical
Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia
| | - Mitja Kelemen
- Jožef
Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
- Jožef
Stefan Institute Postgraduate School, Jamova 39, 1000 Ljubljana, Slovenia
| | - Marjana Regvar
- Biotechnical
Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia
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Jeromel L, Ogrinc N, Siketić Z, Vavpetič P, Rupnik Z, Bučar K, Jenčič B, Kelemen M, Vencelj M, Vogel-Mikuš K, Kovač J, Heeren RMA, Flinders B, Cuypers E, Barba Ž, Pelicon P. Molecular imaging of humain hair with MeV-SIMS: A case study of cocaine detection and distribution in the hair of a cocaine user. PLoS One 2022; 17:e0263338. [PMID: 35333862 PMCID: PMC8956162 DOI: 10.1371/journal.pone.0263338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 01/17/2022] [Indexed: 11/18/2022] Open
Abstract
Human hair absorbs numerous biomolecules from the body during its growth. This can act as a fingerprint to determine substance intake of an individual, which can be useful in forensic studies. The cocaine concentration profile along the growth axis of hair indicates the time evolution of the metabolic incorporation of cocaine usage. It could be either assessed by chemical extraction and further analysis of hair bundels, or by direct single hair fibre analysis with mass spectroscopy imaging (MSI). Within this work, we analyzed the cocaine distribution in individual hair samples using MeV-SIMS. Unlike conventional surface analysis methods, we demonstrate high yields of nonfragmented molecular ions from the surface of biological materials, resulting in high chemical sensitivity and non-destructive characterisation. Hair samples were prepared by longitudinally cutting along the axis of growth, leaving half-cylindrical shape to access the interior structure of the hair by the probing ion beam, and attached to the silicon wafer. A focused 5.8 MeV 35Cl6+ beam was scanned across the intact, chemically pristine hair structure. A non-fragmented protonated [M+ H]+ cocaine molecular peak at m/z = 304 was detected and localized along the cross-section of the hair. Its intensity exhibits strong fluctuations along the direction of the hair’s growth, with pronounced peaks as narrow as 50 micrometres, corresponding to a metabolic incorporation time of approx. three hours.
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Affiliation(s)
| | - Nina Ogrinc
- The Maastricht MultiModal Molecular Imaging Institute, Maastricht University, ER Maastricht, Maastricht, The Netherlands
| | | | | | | | | | | | | | | | - Katarina Vogel-Mikuš
- Jožef Stefan Institute, SI-Ljubljana, Slovenia
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Janez Kovač
- Jožef Stefan Institute, SI-Ljubljana, Slovenia
| | - Ron M. A. Heeren
- The Maastricht MultiModal Molecular Imaging Institute, Maastricht University, ER Maastricht, Maastricht, The Netherlands
| | - Bryn Flinders
- The Maastricht MultiModal Molecular Imaging Institute, Maastricht University, ER Maastricht, Maastricht, The Netherlands
| | - Eva Cuypers
- The Maastricht MultiModal Molecular Imaging Institute, Maastricht University, ER Maastricht, Maastricht, The Netherlands
- KU Leuven Toxicology & Pharmacology, Leuven, Belgium
| | - Žiga Barba
- Jožef Stefan Institute, SI-Ljubljana, Slovenia
- * E-mail:
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Jenčič B, Vavpetič P, Kelemen M, Pelicon P. Secondary Ion Yield and Fragmentation of Biological Molecules by Employing 35Cl Primary Ions within the MeV Energy Domain. J Am Soc Mass Spectrom 2020; 31:117-123. [PMID: 32881522 DOI: 10.1021/jasms.9b00019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
MeV-SIMS is an emerging mass spectrometry imaging method that employs fast, heavy ions to desorb secondary molecules from the analyzed sample. High yields and low fragmentation rates of large molecules, associated with the dominating electronic sputtering process, make it particularly useful in biomedical research, where insight into the distribution of organic molecules is vital. Both yield and fragmentation of desorbed molecules in MeV-SIMS rely on characteristics of the primary ion but may also be impaired by poor instrumental settings. After utilizing secondary ion optics in the linear mass spectrometer at the micro-analytical center of the Jožef Stefan Institute, we demonstrate very efficient detection of secondary ions. As a result, the secondary ion yield, using such settings, solely depends on the species and the characteristics of the primary ion. In order to analyze the yield dependence on the primary ion energy, and the corresponding stopping power within the electronic excitation regime, we used a continuous electron multiplier detector to measure the primary ion current during each measurement of the mass spectra. Secondary ion yield as a function of the primary ion energy and charge is presented as well as fragmentation rates of organic molecules arginine and leu-enkephalin. Other influential instrumental drawbacks are also studied, and their effect on the results is discussed.
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Affiliation(s)
- Boštjan Jenčič
- Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Primož Vavpetič
- Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Mitja Kelemen
- Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Primož Pelicon
- Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
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Jenčič B, Vavpetič P, Kelemen M, Vencelj M, Vogel-Mikuš K, Kavčič A, Pelicon P. MeV-SIMS TOF Imaging of Organic Tissue with Continuous Primary Beam. J Am Soc Mass Spectrom 2019; 30:1801-1812. [PMID: 31250317 DOI: 10.1007/s13361-019-02258-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/23/2019] [Accepted: 05/23/2019] [Indexed: 06/09/2023]
Abstract
MeV-SIMS is an emerging mass spectrometry imaging method, which utilizes fast, heavy ions to desorb secondary molecules. High yields and low fragmentation rates of large molecules, associated with the electronic sputtering process, make it particularly useful in biomedical research, where insight into distribution of organic molecules is needed. Since the implementation of MeV-SIMS in to the micro-beam line at the tandem accelerator of Jožef Stefan Institute, MeV-SIMS provided some valuable observations on the distribution of biomolecules in plant tissue, as discussed by Jenčič et al. (Nucl. Inst. Methods Phys. Res. B. 371, 205-210, 2016; Nucl. Inst. Methods Phys. Res. B. 404, 140-145, 2017). However, limited focusing ability of the chlorine ion beam only allowed imaging at the tissue level. In order to surpass shortcomings of the existing method, we introduced a new approach, where we employ a continuous, low-current primary beam. In this mode, we bombard thin samples with a steady chlorine ion flux of approx. 5000 ions/s. After desorbing molecules, chlorine ions penetrate through the thinly cut sample and trigger the time-of-flight "start" signal on a continuous electron multiplier detector, positioned behind the sample. Such bombardment is more effective than previously used pulsing-beam mode, which demanded several orders of magnitude higher primary ion beam currents. Sub-micrometer focusing of low-current primary ion beam allows imaging of biological tissue on a subcellular scale. Simultaneously, new time-of-flight acquisition approach also improves mass resolution by a factor of 5. Within the article, we compare the performance of both methods and demonstrate the application of continuous mode on biological tissue. We also describe the thin sample preparation protocol, necessary for measurements with low primary ion currents.
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Affiliation(s)
- Boštjan Jenčič
- Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia
| | - Primož Vavpetič
- Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia
| | - Mitja Kelemen
- Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia
| | - Matjaž Vencelj
- Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia
| | - Katarina Vogel-Mikuš
- Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia
- Biotechnical Faculty, Department of Biology, University of Ljubljana, Večna pot 11, SI-1000, Ljubljana, Slovenia
| | - Anja Kavčič
- Biotechnical Faculty, Department of Biology, University of Ljubljana, Večna pot 11, SI-1000, Ljubljana, Slovenia
| | - Primož Pelicon
- Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia.
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Pongrac P, Serra TS, Castillo-Michel H, Vogel-Mikuš K, Arčon I, Kelemen M, Jenčič B, Kavčič A, Villafort Carvalho MT, Aarts MGM. Cadmium associates with oxalate in calcium oxalate crystals and competes with calcium for translocation to stems in the cadmium bioindicator Gomphrena claussenii. Metallomics 2018; 10:1576-1584. [DOI: 10.1039/c8mt00149a] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Cd binds to oxalate crystals, where it replaces Ca in the vacuoles of a bioindicator plant Gomphrena clausenii.
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Affiliation(s)
- Paula Pongrac
- Biotechnical Faculty
- University of Ljubljana
- SI-1000 Ljubljana
- Slovenia
- Jožef Stefan Institute
| | - Tânia S. Serra
- Laboratory of Genetics
- Wageningen University and Research
- 6708 PB Wageningen
- The Netherlands
| | | | - Katarina Vogel-Mikuš
- Biotechnical Faculty
- University of Ljubljana
- SI-1000 Ljubljana
- Slovenia
- Jožef Stefan Institute
| | - Iztok Arčon
- Jožef Stefan Institute
- SI-1000 Ljubljana
- Slovenia
- University of Nova Gorica
- SI-5000 Nova Gorica
| | | | | | - Anja Kavčič
- Biotechnical Faculty
- University of Ljubljana
- SI-1000 Ljubljana
- Slovenia
| | | | - Mark G. M. Aarts
- Laboratory of Genetics
- Wageningen University and Research
- 6708 PB Wageningen
- The Netherlands
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