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Sun M, Otsuka Y, Okada M, Shimma S, Toyoda M. Probe oscillation control in tapping-mode scanning probe electrospray ionization for stabilization of mass spectrometry imaging. Analyst 2024; 149:4011-4019. [PMID: 38953117 DOI: 10.1039/d4an00712c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/03/2024]
Abstract
Mass spectrometry imaging (MSI) is used for visualizing the distribution of components in solid samples, such as biological tissues, and requires a technique to ionize the components from local areas of the sample. Tapping-mode scanning probe electrospray ionization (t-SPESI) uses an oscillating capillary probe to extract components from a local area of a sample with a small volume of solvent and to perform electrospray ionization of those components at high speed. MSI can be conducted by scanning the sample surface with a capillary probe. To ensure stable extraction and ionization for MSI, the probe oscillation during measurements must be understood. In this study, we examined the changes in oscillation amplitude and phase due to the interaction between the oscillating probe and the brain tissue section when the probe tip was dynamically brought close to the sample surface. The changes in the probe oscillation depended on the oscillation frequency and polarity of the bias voltage applied to the solvent because an electrostatic force shifted the frequency of the probe oscillation. These findings suggest that controlling the probe oscillation frequency is important for stabilizing MSI by t-SPESI.
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Affiliation(s)
- Mengze Sun
- Department of Physics, Graduate School of Science, Osaka University, Japan.
| | - Yoichi Otsuka
- Department of Physics, Graduate School of Science, Osaka University, Japan.
- Forefront Research Center, Graduate School of Science, Osaka University, Japan
| | - Maki Okada
- Department of Physics, Graduate School of Science, Osaka University, Japan.
| | - Shuichi Shimma
- Department of Bioengineering, Graduate School of Engineering, Osaka University, Japan
| | - Michisato Toyoda
- Department of Physics, Graduate School of Science, Osaka University, Japan.
- Forefront Research Center, Graduate School of Science, Osaka University, Japan
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2
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Otsuka Y, Ote N, Sun M, Shimma S, Urakawa O, Yamaguchi S, Kudo T, Toyoda M. Solvent effects of N, N-dimethylformamide and methanol on mass spectrometry imaging by tapping-mode scanning probe electrospray ionization. Analyst 2023; 148:1275-1284. [PMID: 36810589 DOI: 10.1039/d2an01953a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Mass spectrometry imaging (MSI) is an effective technique for visualizing the distribution of lipids in tissues. The direct extraction-ionization methods using minute volumes of solvent for local components have the advantage of rapid measurement without any sample pretreatment. For effective MSI of tissues, it is necessary to understand the effect of solvent physicochemical properties on ion images. In this study, we report solvent effects on the lipid imaging of mouse brain tissue by tapping-mode scanning probe electrospray ionization (t-SPESI) which is capable of extraction-ionization using sub-pL solvents. To precisely measure lipid ions, we developed a measurement system incorporating a quadrupole-time-of-flight mass spectrometer. The differences in signal intensity and spatial resolution of lipid ion images were investigated using N,N-dimethylformamide (non-protic polar solvent), methanol (protic polar solvent) and their mixture. The mixed solvent was suitable for the protonation of lipids, and it provided high spatial resolution MSI. Results indicate that the mixed solvent improves the extractant transfer efficiency and minimizes charged droplets from an electrospray. The solvent selectivity study revealed the importance of solvent selection based on physicochemical properties for the advancement of MSI by t-SPESI.
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Affiliation(s)
- Yoichi Otsuka
- Department of Physics, Graduate School of Science, Osaka University, Japan. .,JST, PREST, Japan.,Forefront Research Center, Graduate School of Science, Osaka University, Japan
| | - Nijiho Ote
- Department of Biological Sciences, School of Science, Osaka Universit, Japan
| | - Mengze Sun
- Department of Physics, Graduate School of Science, Osaka University, Japan.
| | - Shuichi Shimma
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Japan
| | - Osamu Urakawa
- Department of Chemistry, Graduate School of Science, Osaka University, Japan
| | | | | | - Michisato Toyoda
- Department of Physics, Graduate School of Science, Osaka University, Japan. .,Forefront Research Center, Graduate School of Science, Osaka University, Japan
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Otsuka Y. Direct Liquid Extraction and Ionization Techniques for Understanding Multimolecular Environments in Biological Systems (Secondary Publication). Mass Spectrom (Tokyo) 2021; 10:A0095. [PMID: 34249586 PMCID: PMC8246329 DOI: 10.5702/massspectrometry.a0095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 11/23/2022] Open
Abstract
A combination of direct liquid extraction using a small volume of solvent and electrospray ionization allows the rapid measurement of complex chemical components in biological samples and visualization of their distribution in tissue sections. This review describes the development of such techniques and their application to biological research since the first reports in the early 2000s. An overview of electrospray ionization, ion suppression in samples, and the acceleration of specific chemical reactions in charged droplets is also presented. Potential future applications for visualizing multimolecular environments in biological systems are discussed.
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Affiliation(s)
- Yoichi Otsuka
- Graduate School of Science, Osaka University, 1–1 Machikaneyama-cho, Toyonaka, Osaka 560–0043, Japan
- JST, PRESTO, 4–1–8 Honcho, Kawaguchi, Saitama 332–0012, Japan
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4
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Otsuka Y, Kamihoriuchi B, Takeuchi A, Iwata F, Tortorella S, Matsumoto T. High-Spatial-Resolution Multimodal Imaging by Tapping-Mode Scanning Probe Electrospray Ionization with Feedback Control. Anal Chem 2021; 93:2263-2272. [PMID: 33400515 DOI: 10.1021/acs.analchem.0c04144] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Direct extraction and ionization techniques using minute amounts of solvent can be employed for the rapid analysis of chemical components in a sample without any sample preparation steps. This type of approach is important for mass spectrometry imaging of samples with multiple chemical components that have different spatial distributions (i.e., biological tissues). To improve the spatial resolution of such imaging, it is necessary to reduce the solvent volume for extraction and deliver it to the sample surface. This report describes a feedback control system applied to tapping-mode scanning probe electrospray ionization. By combining the measurement technique of capillary probe vibration with the dynamic distance control system between the probe and the sample, the vibration amplitude of the probe is maintained while the probe scans over uneven samples. This method allows simultaneous high-resolution imaging of molecular distribution, surface topography, and amplitude/phase changes in the probe vibration. Such multimodal imaging is demonstrated on rhodamine B thin films in microwells and on a mouse brain tissue section. This technique can generally be applied to examine the multidimensional molecular distribution and the surface profiles of various objects.
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Affiliation(s)
- Yoichi Otsuka
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Bui Kamihoriuchi
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Aya Takeuchi
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Futoshi Iwata
- Graduate School of Integrated Science and Technology, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu, Shizuoka 432-8561, Japan
| | - Sara Tortorella
- Molecular Horizon Srl, Via Montelino 30, 06084 Bettona, Perugia, Italy
| | - Takuya Matsumoto
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
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6
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rMSIKeyIon: An Ion Filtering R Package for Untargeted Analysis of Metabolomic LDI-MS Images. Metabolites 2019; 9:metabo9080162. [PMID: 31382415 PMCID: PMC6724114 DOI: 10.3390/metabo9080162] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 07/23/2019] [Accepted: 07/30/2019] [Indexed: 12/25/2022] Open
Abstract
Many MALDI-MS imaging experiments make a case versus control studies of different tissue regions in order to highlight significant compounds affected by the variables of study. This is a challenge because the tissue samples to be compared come from different biological entities, and therefore they exhibit high variability. Moreover, the statistical tests available cannot properly compare ion concentrations in two regions of interest (ROIs) within or between images. The high correlation between the ion concentrations due to the existence of different morphological regions in the tissue means that the common statistical tests used in metabolomics experiments cannot be applied. Another difficulty with the reliability of statistical tests is the elevated number of undetected MS ions in a high percentage of pixels. In this study, we report a procedure for discovering the most important ions in the comparison of a pair of ROIs within or between tissue sections. These ROIs were identified by an unsupervised segmentation process, using the popular k-means algorithm. Our ion filtering algorithm aims to find the up or down-regulated ions between two ROIs by using a combination of three parameters: (a) the percentage of pixels in which a particular ion is not detected, (b) the Mann–Whitney U ion concentration test, and (c) the ion concentration fold-change. The undetected MS signals (null peaks) are discarded from the histogram before the calculation of (b) and (c) parameters. With this methodology, we found the important ions between the different segments of a mouse brain tissue sagittal section and determined some lipid compounds (mainly triacylglycerols and phosphatidylcholines) in the liver of mice exposed to thirdhand smoke.
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Kamihoriuchi B, Otsuka Y, Takeuchi A, Iwata F, Matsumoto T. Visualization of Sampling and Ionization Processes in Scanning Probe Electrospray Ionization Mass Spectrometry. ACTA ACUST UNITED AC 2019; 7:S0078. [PMID: 31840014 PMCID: PMC6863452 DOI: 10.5702/massspectrometry.s0078] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 12/25/2018] [Indexed: 02/05/2023]
Abstract
Ambient sampling and ionization techniques based on direct liquid extraction and electrospray ionization are of great value for rapid analysis and mass spectrometry imaging. Scanning probe electrospray ionization (SPESI) enables the sampling and ionization of analyte molecules in a solid material using a liquid bridge and electrospray, respectively, from a single capillary probe. To further improve SPESI, it is essential to understand the dynamic behavior of nanoliter volumes of liquids during sampling and ionization. In this study, the dynamic formation and breakage of the liquid bridge and the subsequent electrospray ionization were investigated by measuring the displacement of the capillary probe using a new optical technique. Measurements revealed that both the time from the formation of the liquid bridge to its breakage and the time from the breakage of the liquid bridge to the detection of analyte ions were correlated with the physical properties of the solvent. It was also found that both of these times were positively correlated with the flow rate. These results will not only lead to the improvement of sampling and ionization efficiencies but also afford a greater understanding of the physicochemical properties of charged nanoliter volumes of liquids.
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Affiliation(s)
- Bui Kamihoriuchi
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Yoichi Otsuka
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Aya Takeuchi
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Futoshi Iwata
- Faculty of Engineering, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561, Japan
| | - Takuya Matsumoto
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
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Picard de Muller G, Ait-Belkacem R, Bonnel D, Longuespée R, Stauber J. Automated Morphological and Morphometric Analysis of Mass Spectrometry Imaging Data: Application to Biomarker Discovery. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:2635-2645. [PMID: 28913742 DOI: 10.1007/s13361-017-1784-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 07/28/2017] [Accepted: 08/10/2017] [Indexed: 06/07/2023]
Abstract
Mass spectrometry imaging datasets are mostly analyzed in terms of average intensity in regions of interest. However, biological tissues have different morphologies with several sizes, shapes, and structures. The important biological information, contained in this highly heterogeneous cellular organization, could be hidden by analyzing the average intensities. Finding an analytical process of morphology would help to find such information, describe tissue model, and support identification of biomarkers. This study describes an informatics approach for the extraction and identification of mass spectrometry image features and its application to sample analysis and modeling. For the proof of concept, two different tissue types (healthy kidney and CT-26 xenograft tumor tissues) were imaged and analyzed. A mouse kidney model and tumor model were generated using morphometric - number of objects and total surface - information. The morphometric information was used to identify m/z that have a heterogeneous distribution. It seems to be a worthwhile pursuit as clonal heterogeneity in a tumor is of clinical relevance. This study provides a new approach to find biomarker or support tissue classification with more information. Graphical Abstract ᅟ.
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Affiliation(s)
| | - Rima Ait-Belkacem
- ImaBiotech SAS, Parc Eurasanté, 885 rue Eugène Avinée, 59120, Loos, France
| | - David Bonnel
- ImaBiotech SAS, Parc Eurasanté, 885 rue Eugène Avinée, 59120, Loos, France
| | - Rémi Longuespée
- Mass Spectrometry Laboratory (LSM), Systems Biology and Chemical Biology, GIGA-Research, University of Liège, Allée du 6 août 11, 4000, Liège, Belgium
- Institute of Pathology, University of Heidelberg, Im Neuenheimer Feld 224, 69120, Heidelberg, Germany
| | - Jonathan Stauber
- ImaBiotech SAS, Parc Eurasanté, 885 rue Eugène Avinée, 59120, Loos, France.
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Kohigashi T, Otsuka Y, Shimazu R, Matsumoto T, Iwata F, Kawasaki H, Arakawa R. Reduced Sampling Size with Nanopipette for Tapping-Mode Scanning Probe Electrospray Ionization Mass Spectrometry Imaging. ACTA ACUST UNITED AC 2016; 5:S0054. [PMID: 28101441 DOI: 10.5702/massspectrometry.s0054] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/07/2016] [Indexed: 11/23/2022]
Abstract
Mass spectrometry imaging (MSI) with ambient sampling and ionization can rapidly and easily capture the distribution of chemical components in a solid sample. Because the spatial resolution of MSI is limited by the size of the sampling area, reducing sampling size is an important goal for high resolution MSI. Here, we report the first use of a nanopipette for sampling and ionization by tapping-mode scanning probe electrospray ionization (t-SPESI). The spot size of the sampling area of a dye molecular film on a glass substrate was decreased to 6 μm on average by using a nanopipette. On the other hand, ionization efficiency increased with decreasing solvent flow rate. Our results indicate the compatibility between a reduced sampling area and the ionization efficiency using a nanopipette. MSI of micropatterns of ink on a glass and a polymer substrate were also demonstrated.
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Affiliation(s)
| | - Yoichi Otsuka
- Department of Chemistry, Graduate School of Science, Osaka University
| | - Ryo Shimazu
- Faculty of Chemistry, Materials and Bioengineering, Kansai University
| | - Takuya Matsumoto
- Department of Chemistry, Graduate School of Science, Osaka University
| | | | - Hideya Kawasaki
- Faculty of Chemistry, Materials and Bioengineering, Kansai University
| | - Ryuichi Arakawa
- Faculty of Chemistry, Materials and Bioengineering, Kansai University
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Affiliation(s)
- Julia Laskin
- Physical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, MSIN K8-88, Richland, WA 99352
| | - Ingela Lanekoff
- Department of Chemistry-BMC, Uppsala University, Box 599, 751 24 Uppsala, Sweden
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