1. Can you please briefly summarize the paper?

Mass Spectrometry Imaging (MSI) encompasses a group of powerful imaging techniques that enable researchers to visualize the spatial distribution of hundreds of biomolecules directly within biological samples using mass spectrometry (MS). Unlike traditional bulk omics methods that average molecular signals and lose spatial information, MSI preserves the native tissue context by scanning the sample surface with an ionization source and recording a mass spectrum at each position. This provides detailed insights into cellular organization, disease mechanisms, and drug effects. As MSI is mainly non-destructive, it can be combined with histological methods such as immunohistochemistry (IHC) or immunofluorescence (IF), allowing for the reuse of valuable clinical samples after measurement. Despite its strengths, MSI faces challenges in detecting large biomolecules such as proteins, which are key therapeutic targets. To address this limitation, On-Tissue Mass-Tag Labeling (OTMT) has been developed. OTMT employs specialized affinity-based probes called Mass-Tags (MTs) that bind to specific biomolecules and release detectable reporter signals upon activation. This approach enables highly multiplexed protein imaging while preserving MSI’s multi-omics capabilities. Traditionally, MTs rely on antibodies as targeting elements and photocleavable organic molecules as reporter groups. However, these components can be costly, difficult to handle, and prone to signal overlap with endogenous molecules.

Overview of the PARPi-MT concept. ACS Cent. Sci. (2025). https://doi.org/10.1021/acscentsci.5c01381

To overcome these drawbacks, our work introduces a new class of MTs that use small-molecule drugs instead of antibodies as targeting motifs, along with photocleavable ruthenium (Ru) complexes as reporter groups. These Ru-based reporters offer unique isotopic signatures, enabling the rapid and unambiguous identification of MT signals within complex datasets. The newly developed PARPi-MT combines the PARP1/2 inhibitor Olaparib with a photocleavable, fluorescent Ru-based reporter to visualize PARP1/2 in tissue sections using both DESI (Desorption Electrospray Ionization)-MSI and fluorescence confocal microscopy (FCM). This innovation expands the design flexibility of MTs and enhances their multimodal imaging potential, paving the way for more versatile spatial proteomics applications.

2. Can you please tell us the main difficulties you had in the laboratory work and how you overcame them?

Finding the right conditions to purify PARPi-MT and to establish a staining workflow that produces clear and reliable imaging results were definitely not straightforward. There were many moments of trial and error, learning from what did not work, discussing ideas with peers, revisiting the literature for inspiration, and testing new approaches. It was a process that truly tested my patience and persistence, but also taught me a lot about problem-solving in science. Ultimately, by remaining curious, open-minded, and resilient, I overcame these challenges. Looking back, I would say this experience taught me that in research, even when a problem seems unsolvable at first, perseverance and creativity can make all the difference.

3. Please introduce your laboratory, university or organization to bio-researchers in Korea.

As a joint PhD student co-supervised by two outstanding professors at the Technical University of Munich, I have the privilege of working across two dynamic and complementary research groups. I am affiliated with the research group of Prof. Dr. Angela Casini, which focuses on Medicinal and Bioinorganic Chemistry, and the group of Prof. Dr. Nicole Strittmatter, which specializes in spatial analysis of biological samples using in situ and ambient mass spectrometry.

The Casini group (Chair of Medicinal and Bioinorganic Chemistry) investigates the role of metal ions in biological systems and explores the mechanisms of action of metal-based anticancer agents. Alongside the synthesis and structural characterization of novel metal complexes, the group places strong emphasis on their biological evaluation as potential therapeutic and imaging agents. The overarching goal is to develop new concepts in drug design that effectively bridge fundamental research and clinical applications. In addition, we explore innovative uses of metal-based molecules and materials, including supramolecular coordination complexes, across diverse fields such as chemical biology, bioanalytical chemistry, radiochemistry, drug delivery, and regenerative medicine. Ultimately, our research aims to expand the boundaries of classical bioinorganic chemistry by integrating insights from organometallic catalysis, supramolecular chemistry, and materials science to advance the development of novel biomedical applications.

The Strittmatter group (Professorship of Analytical Chemistry) focuses on in situ and ambient mass spectrometry in the context of metabolomics. The group develops cutting-edge methods that enable the direct analysis of molecules in their native biological context, whether in bacterial cultures, clinical tissue sections, or soils. Key capabilities include Mass Spectrometry Imaging (MSI), utilizing ambient techniques such as DESI (Desorption Electrospray Ionization) or LD REIMS (Laser Desorption Rapid Evaporative Ionization MS), which enables the generation of spatial maps of metabolites, lipids, and xenobiotics across tissue sections. The goal is to link molecular information, such as the production of a certain secondary metabolite or a drug metabolite, to the underlying cellular map of the tissue environment in order to produce actionable biological insights.

If you would like to learn more about our research, please visit our groups’ websites:

Chair of Medicinal and Bioinorganic Chemistry (Prof. Casini): https://www.ch.nat.tum.de/mbc/home/

Professorship of Analytical Chemistry (Prof. Strittmatter): https://www.bio.nat.tum.de/ach/home/

Applications from highly motivated students and researchers are always welcome. Please contact us to explore opportunities for open positions, research stays, or collaborative projects. We look forward to hearing from you!

4. Please tell us your experiences and your thoughts related to research activities abroad.

Working in two international and interdisciplinary groups, where different cultures, scientific backgrounds, and collaborative spirits come together, has taught me that science is not a solo endeavor but a true team sport. Collaboration is essential: Not only for carrying out studies that one person alone could never achieve, but also for gaining new perspectives and experiences that spark fresh ideas and innovation.
Living and growing up in a foreign country was certainly not easy. There were challenges you would not face at home in Korea, but these experiences are incredibly enriching. They shape you into a better researcher, someone who can bridge cultures and disciplines, communicate across differences, and appreciate the value of diverse viewpoints.
My advice is: Do not be afraid to challenge yourself and step outside your comfort zone. You will always find peers who are willing to help and support you, and you are never truly alone. And if you are living abroad, even if it is only for a short time, take the opportunity to travel, learn the language, and immerse yourself in the local culture. These experiences will not only enrich your life but also shape your future career and perspective as a scientist.

5. Can you provide some advice for younger scientists who have plans to study abroad?

Before applying, take the time to learn what the group is working on and how their research aligns with your own interests and goals. Think about how you can contribute with your own skills, but also what you can learn from them. Of course, joining a well-known group at a prestigious university is valuable, but it is just as important to consider what you want to achieve from your research stay abroad and whether the group offers an environment where you can grow and feel supported.
The success of your research largely depends on your own efforts and achievements, but having a positive and motivating environment can make a huge difference. At the same time, this relationship goes both ways: You need to show openness, a willingness to interact, and a genuine effort to integrate into the group. Research is not only about experiments and data, but it is also about people, communication, and collaboration. Do not be afraid of criticism. Instead, embrace it as an opportunity to grow and adapt. Constructive feedback and open, two-way communication between student and supervisor are essential to reaching the goals you are striving for. Good English skills are certainly helpful, but do not be discouraged if you are still improving. Showing enthusiasm and a willingness to learn goes a long way and often matters even more. And finally, if possible, try to arrange a meeting with your potential supervisor and future lab members before making your decision. It can give you a real sense of the group’s atmosphere and whether it is the right fit for you.

6. Future plan?

I am currently in the final stretch of my PhD, finishing my thesis and preparing for my defense. It has been an exciting time to reflect on the work I have done and the skills I have gained. After graduation, I plan to apply for my first postdoctoral position and early-career grants, such as the Marie Skłodowska-Curie Fellowship. I view this as an opportunity to broaden my scientific horizons, develop new skills, and tackle new challenges in diverse research environments. I am also looking forward to meeting new colleagues, building connections, and finding groups where I can contribute and grow as a scientist.

7. Do you have anything else that you would like to tell Korean scientists and students?

I sincerely thank my two wonderful research groups and supervisors for their guidance and support throughout my PhD, as well as all the collaborators who contributed to my research. I have learned so much from them, and I am genuinely grateful to have been part of such inspiring and supportive communities. Working with them has always been a pleasure, and many of the group members have become not just colleagues, but friends for life! Beyond my research groups, the Korean Scientists and Engineers Association in Germany (VeKNI e.V.) has provided me with incredible opportunities to network with fellow Korean scientists in Germany and participate in exciting programs, such as the Young Professional Forum hosted by the Korean Federation of Science and Technology Societies (KOFST). If you ever come to Germany for a research stay and want to connect with other Korean scientists and students, I highly recommend joining VeKNI e.V. It opens the door to diverse events and allows you to meet scientists at all career stages and in various fields.

Check it out here: https://www.vekni.org