Learn the principle,
Utilize it for life quality.

Presentation

2025.7.27-8.1
We have presented recent results at the Chemical Imaging Gordon Research Conference.

• t-SPESI: Rapid Extraction-Ionization Technique for Mass Spectrometry Imaging of Tissues and Cells (Poster & Short Talk)
  Yoichi Otsuka, Mengze Sun, Yang Zhou, Takao Yasuda, Shuichi Shimma, Michisato Toyoda

Presentation

2025.6.24-25
We have presented recent results at the 10th Asia-Oceania Mass Spectrometry Conference (AOMSC2025).

• Investigation of Extraction-Ionization Process of t-SPESI by Current Measurement  (Poster)
  Mengze Sun, Yoichi Otsuka, Lee Chuin Chen, Michisato Toyoda 

• Development of a Compact t-SPESI System for High-sensitivity Mass Spectrometry Imaging of Biological Tissue  (Poster)
  Yoichi Otsuka, Takao Yasuda, Mengze Sun, Zhou Yang, Shuichi Shimma, Michisato Toyoda

Paper

2025.5.28
The following paper was published.

• Mass Spectrometry Imaging of Time-Dependently Photodegraded Light Stabilizers in Polyethylene Films Using Tapping-Mode Scanning Probe Electrospray Ionization
  Tsuyoshi Akiyama, Yoichi Otsuka, Mengze Sun, Shinichi Yamaguchi, Michisato Toyoda
  Mass Spectrometry (Tokyo),
  https://doi.org/10.5702/massspectrometry.A0173

Paper

2025.5.22
The following paper was published.

• Meeting Report: The Japanese-German Symposium on the "Advancement and Application of Proteoform-Centric Proteomics" (Kyoto, Japan, 2024)
  Nobuaki Takemori, Philipp T. Kaulich, Jan Hahn, Hartmut Schlüter, Naoyuki Sugiyama, Kazuya Tsumagari, Yasushi Ishihama, Sabine Fuchs, Mio Iwasaki, Franz-Josef Müller, Christian Neusüß, Kyowon Jeong, Oliver Kohlbacher, Yoshihiro Shimizu, Yoichi Otsuka, Hisako Sato, Kazuki Sasaki, Yuriko Minegishi, Yoshio Kodera, Irene Fernandez-Cuesta, Boris Krichel, Norie Araki, Andreas Tholey
  Proteomics, 2025; 0:e202400394
  https://doi.org/10.1002/pmic.202400394

Paper

2025.5.14
The following paper was published.

• Single-Cell Mass Spectrometry Imaging of Lipids in HeLa Cells via Tapping-Mode Scanning Probe Electrospray Ionization,
  Yoichi Otsuka*, Kazuya Kabayama, Ayane Miura, Masatomo Takahashi, Kosuke Hata, Yoshihiro Izumi, Takeshi Bamba, Koichi Fukase, Michisato Toyoda, Communications Chemistry, 8, 147 (2025).
  https://doi.org/10.1038/s42004-025-01521-2

Paper

2024.11.22
The following paper was published.

• Improved ion detection sensitivity in mass spectrometry imaging using tapping‑mode scanning probe electrospray ionization to visualize localized lipids in mouse testes
  Yoichi Otsuka, Maki Okada, Tomomi Hashidate-Yoshida, Katsuyuki Nagata, Makoto Yamada, Motohito Goto, Mengze Sun, Hideo Shindou, Michisato Toyoda
  Analytical and Bioanalytical Chemistry (2024).
  https://doi.org/10.1007/s00216-024-05641-x

Presentation

2024.9.12
We have presented  recent results at 2nd Annual Conference on Mass Spectrometry Imaging and Integrated Topics (IMSIS 2024)

• (Oral, Keynote) High-Spatial-Resolution Mass Spectrometry Imaging of Phospholipids in Biosynthesis-Impaired Mouse Tissues via Tapping-Mode Scanning Probe Electrospray Ionization
  Yoichi Otsuka, Maki Okada, Mengze Sun, Tomomi Hashidate-Yoshida, Katsuyuki Nagata, Makoto Yamada, Motohito Goto, Hideo Shindou, Michisato Toyoda

Presentation

2024.8.26
We have presented  recent results at International Mass Spectrometry Conference 2024 (IMSC 2024)

• (Oral) Mass spectrometry imaging of a single HeLa cell by tapping-mode scanning probe electrospray ionization
  Yoichi Otsuka, Kazuya Kabayama, Ayane Miura, Masatomo Takahashi, Kosuke Hata, Yoshihiro Izumi, Takeshi Bamba, Koichi Fukase, Michisato Toyoda

• (Oral)Mass Spectrometry Imaging of LPLAT8 Knockout Mouse Retina by Tapping-mode Scanning Probe Electrospray Ionization
  Mengze Sun, Yoichi Otsuka , Katsuyuki Nagata , Hideo Shindou , Akiyoshi Hirayama, Michisato Toyoda 

Paper

2024.7.2
The following paper was published.

Probe oscillation control in tapping-mode scanning probe electrospray ionization for stabilization of mass spectrometry imaging
Mengze Sun, Yoichi Otsuka, Maki Okada, Shuichi Shimma, Michisato Toyoda
Analyst, (2024).
https://doi.org/10.1039/D4AN00712C

Presentation

2024.6.4
We have presented  recent results at 72nd ASMS Conference on Mass Spectrometry and Allied Topics.

• High-Spatial-Resolution Mass Spectrometry Imaging of Phospholipids in Biosynthesis-Impaired Mouse Testis via Tapping-Mode Scanning Probe Electrospray Ionization

Yoichi Otsuka, Maki Okada, Tomomi Hashidate-Yoshida, Katsuyuki Nagata, Makoto Yamada, Motohito Goto, Mengze Sun, Hideo Shindou, Michisato Toyoda

Presentation

2023.10.28
We have presented recent results at Annual Conference on Mass Spectrometry Imaging and Integrated Topics (1st IMSIS Conference)
https://imsis2023.org/

• Mass Spectrometry Imaging of Single Cells by Tapping-mode Scanning Probe Electrospray Ionization

Yoichi Otsuka, Kazuya Kabayama, Ayane Miura, Koichi Fukase, Michisato Toyoda

Presentation

2023.8.27
We have presented  recent results at AOMSC-KSMS 2023.

• Control and Utilize Periodic Motions for the Development of Time-of-flight Mass Spectrometer and Ambient Sampling-Ionization Technique (Invited Talk)
  Yoichi Otsuka, Michisato Toyoda

• Development of a real-time soil-gas measurement system using a multi-turn time-of-flight mass spectrometer (Poster)
  Shunya Suzuki, Yo Toma, Toshinobu Hondo, Yosuke Kawai, Yoichi Otsuka, Michisato Toyoda

• Effect of Probe Oscillation Frequency on Mass Spectrometry Imaging of Mouse Brain Sections by t-SPESI (Poster)
  Mengze Sun, Yoichi Otsuka, Maki Okada, Shuichi Shimma, Michisato Toyoda

Presentation

2023.5.30

We have presented  recent results at 71st ASMS Conference on Mass Spectrometry and Allied Topics.

• Mass spectrometry imaging of single cells by tapping-mode scanning probe electrospray ionization
  Yoichi Otsuka, Kazuya Kabayama, Ayane Miura, Koichi Fukase, Michisato Toyoda

Paper

2023.2.2
The following paper was published.

Solvent effects of N,N-dimethylformamide and methanol on mass spectrometry imaging by tapping-mode scanning probe electrospray ionization
Otsuka, Nijiho One, Mengze Sun, Shuichi Shimma, Osamu Urakawa, Tomoya Kudo, Shinichi Yamaguchi and Michisato Toyoda,
Analyst, (2023). (Open Access)
https://doi.org/10.1039/D2AN01953A.

Paper

2023.1.16
The following paper was published.

Advances in Mass Spectrometry Imaging for Visualization of Cellular Information in Biological Tissues
Yoichi Otsuka, Proteome Letters, 7, 53-62 (2022). https://doi.org/10.14889/jpros.7.2_53
(Japanese)

Open Seminar

2023.1.10

"Frontiers of Ionization and Mass Spectrometry"

In cells, which are the basic units of living organisms, life activities are maintained by the complex interactions of a wide variety of molecules. The development of ionization methods in mass spectrometry has made it possible to visualize the distribution of components in biological tissues and to perform highly sensitive measurements, which is expected to expand the range of utilization of mass spectrometry from basic to applied fields. 

In this workshop, three lecturers are invited to talk about the development of ionization methods and their application research. The seminar will provide an opportunity to learn about state-of-the-art research and discuss the future of ionization methods.

Date & Time: January 28, 2023, 13:30-17:00

Venue: Osaka University, Graduate School of Science (Room H701) and Zoom webinar (Hybrid meeting)

Registration: https://forms.gle/M8S2N7i2j3WapbWMA

Registration Fee: Free

Program:

13:30-13:35 Opening remarks

13:35～14:35 Lecture 1: Dr. Julia Laskin (Purdue University) “Ambient Imaging of Biological Tissues Using Nanospray Desorption Electrospray Ionization (nano-DESI) Mass Spectrometry”

14:35～15:35 Lecture 2: Dr. Toshinobu Hondo (Osaka University) “Supercritical fluid chromatography-proton transfer reaction (water ion chemical) ionization mass spectrometry — Endeavor to a single-cell metabolite determination”

15:35～15:50 Break

15:50～16:50 Lecture 3: Dr. Cheng Li-Chuin (University of Yamanashi) “In pursuit of novel applications using super-atmospheric pressure ionization mass spectrometry”

16:50-17:00 Closing remarks

Organizer: Yoichi Otsuka (Osaka University), Rika Miyake (Osaka University), Takae Takeuchi (Nara Women's University)

Contact: Yoichi Otsuka (Osaka University) E-mail: Otsuka “at-sign” phys.sci.osaka-u.ac.jp

Presentation

2023.1.10

We will present our recent results at International Mass Spectrometry Imaging Symposium (IMSMI) 2023 Kyoto
https://www.kbmss.org/sympo6-poster/

• Effect of Probe Vibration Frequency on Tapping-Mode Scanning Probe Electrospray Ionization
  Mengze Sun, Yoichi Otsuka, Maki Okada, Shuichi Shimma, Michisato Toyoda

• Mass Spectrometry Imaging of mouse testis by tapping mode scanning probe electrospray ionization
  Maki Okada, Yoichi Otsuka, Sun Mengze, Hideo Shindou, Tomomi Yoshida, Michisato Toyoda

• Development of tapping-mode scanning probe electrospray ionization for lipid imaging of tissues
  Yoichi Otsuka, Shuichi Shimma, Hidataka Kioka, Tomohito Ohtani, Yasushi Sakata

Paper

2022.5.4

The following paper was published.

Shape-Dependent Conduction Regime in Self-Doped Polyaniline

Jiannan Bao, Yoichi Otsuka, Hiroshi Ohoyama, and Takuya Matsumoto

J. Phys. Chem. C (2022)

https://doi.org/10.1021/acs.jpcc.1c10929

Paper

2022.1.5

The following paper was published.

In-Materio Reservoir Computing in a Sulfonated Polyaniline Network

Yuki Usami, Bram van de Ven, Dilu G. Mathew, Tao Chen, Takumi Kotooka, Yuya Kawashima, Yuichiro Tanaka, Yoichi Otsuka, Hiroshi Ohoyama, Hakaru Tamukoh, Hirofumi Tanaka, Wilfred G. van der Wiel, Takuya Matsumoto

Advanced Materials, 33, 2102688 (2021).

https://doi.org/10.1002/adma.202102688

Award

2021.12.8

We received the presentation award 

Name of Conference: The Chemical Society of Japan Fall Meeting, The 11th CSJ Chemistry Festa 2021

Name of Award: Excellent Poster Presentation Award

Recipient:  Yuto Itoi (Department of Chemistry, Graduate School of Science, Osaka University)

Title of Presentation: Rapid Derivatization Reaction of Peptides Using Micro-Charged Droplets

Date of Award：2021/12/1

https://www.sci.osaka-u.ac.jp/ja/info/9943/

Award

2021.08.29

We received the presentation award 

Name of Conference: The 15th Kinki Branch Summer Seminar for Young Researchers in 2021

Name of Award: "Science Art Award"

Recipient: Niho Ohte (Department of Biological Sciences, Faculty of Science, Osaka University)

Presentation title: Solvent selectivity of lipid measurement using scanning probe electrospray ionization mass spectrometry

https://www.sci.osaka-u.ac.jp/ja/info/9560/

Paper

2021.07.01

The following paper was published.

Direct Liquid Extraction and Ionization Techniques for Understanding Multimolecular Environments in Biological Systems

Yoichi Otsuka

Mass Spectrometry 10, A0095 (2021).
https://doi.org/10.5702/massspectrometry.A0095T

Paper

2021.04.16

The following paper was published.

Tapping-mode scanning probe electrospray ionization: fusion of SPM with mass spectrometry
Yoichi Otsuka
Jpn. J. Appl. Phys. 60 SE0802  (2021).
https://doi.org/10.35848/1347-4065/abefac

Promotion

2021.04.25
I have been appointed as an associate professor in the mass spectrometry group (Prof. Michisato Toyoda's laboratory), department of physics, graduate school of science, Osaka University.

Paper

2021.02.25
The following article is published.

Sacrificial gold coating enhances transport of liquid metal in pressurized fountain pen lithography
Gideon I. Livshits, Jiannan Bao, Leo Sakamoto, Tomoki Misaka, Yuki Usami, Yoichi Otsuka, Takuya Matsumoto
Sci. Rep. (2021) 11:4670.
https://www.nature.com/articles/s41598-021-84065-4.pdf

Paper

2021.01.06
The following article is published.

High spatial resolution multi-modal imaging by tapping-mode scanning probe electrospray ionization with feedback control
Yoichi Otsuka*, Bui Kamihoriuchi, Aya Takeuchi, Futoshi Iwata, Sara Tortorella, Takuya Matsumoto,
Analytical Chemistry,
https://doi.org/10.1021/acs.analchem.0c04144.

Paper

2020.12.18
The following article is published.

Homogeneous chemical state of self-doped polyaniline sub-micrometer thickness lines fabricated by fountain-pen lithography
Jiannan Bao, Yoichi Otsuka*, Takuya Matsumoto*
Jpn. J. Appl. Phys. 60, 015002 (2020)
https://iopscience.iop.org/article/10.35848/1347-4065/abd04e

Award (MSSJ RESEARCH AWARD)

2020.07.06
We received the MSSJ Research Award for our research.

Award recipient: Yoichi Otsuka
Award contents: Research and development of scanning probe electrospray ionization
http://www.mssj.jp/about/awards.html

We would like to thank everyone involved.

Paper

2020.06.27
The following article is published.

Local-field-induced current noise in shape-limited self-doped polyaniline
Jiannan Bao, Yoichi Otsuka, Riko Etoh, Yuki Usami and Takuya Matsumoto
Nanotechnology 31, 365203 (2020).
https://iopscience.iop.org/article/10.1088/1361-6528/ab96e4

Presentation (ASEAN-OU Chemistry Symposium 2020)

2020.01.17
We have presented our recent results at the ASEAN-OU Chemistry Symposium 2020

Development of scanning probe electrospray ionization for the visualization of chemical components in biological tissue
Yoichi Otsuka

Presentation (AOMSC2020)

2020.01.09
We have presented our recent results at the 8th Asia-Oceania Mass Spectrometry Conference 2020.

Mass spectrometry imaging of human heart tissue by scanning probe electrospray ionization mass spectrometry with feedback control system
Yoichi Otsuka, Bui Kamihoriuchi, Aya Takeuchi, Shuichi Shimma, Hiroshi Miyawaki, Hidetaka Kioka, Tomohito Otani, Yasushi Sakata, Takuya Matsumoto