Highly Cited Researchers Spotlight Series: Kimoon Kim

Field of Study

A molecule called cucurbituril is the key subject of my studies. This cyclic molecule is made from glycoluril and formaldehyde and looks like a hollow pumpkin-shaped container. This molecule can contain smaller molecules and may consequently be used as a tool for stabilizing unstable compounds and can also act as a delivery vehicle. In the past, only the molecule containing 6 glycoluril units was known, but my students and I learned that there is a family of cucurbituril homologues which come in different sizes, ranging from 5 to 11 glycoluril units. We separated the cucurbiturils that contained 5, 7 or 8 units so that we could study their chemistry individually. Depending on the number of glycoluril units contained, the size of the molecule can vary, and the size of molecules that it can accommodate changes accordingly. There is a bonding force between the cucurbiturils and the molecules they contain; when the “guest” molecule is well-designed, this force can be as strong as biotin-avidin, which is the benchmark for strong interaction found in nature. Avidin is a large protein that has many different points of connection with biotin, which causes the strong binding. Thus, it has been a difficult task to replicate this strong binding with much smaller molecules. Cucurbiturils have emerged as a timely solution to problems in many areas. In the field of materials, for example, they can be used as sensors or adhesives. They can also be used in bioscience as a drug-delivery vehicle that lowers drug side effects, such as toxicity, etc.

Why I Chose This Subject

When I began as a professor at POSTECH in 1988, I wanted to study my own subject instead of continuing the old subject I had studied in the United States. In 1991, I read a research paper on cucurbituril in the library and became interested in this molecule. It is a symmetrically beautiful molecule and is easily synthesized in just two steps. Another reason I chose this as my field was that there was no other researcher aside from the one who published a paper in 1981. Although it was part of organic chemistry, which was different from my original field of study, I felt motivated to begin studying it because I wanted to do my own thing, and I was very interested in this field.

Challenges and Solutions

The five years I spent studying cucurbituril was a hard time in my life. No matter how hard I tried, I was not able to produce good results. I was enormously stressed out during my studies, and my health deteriorated. I even thought of stopping the project immediately after publishing a paper. I spent my sabbatical year in 1995 at MIT, during which time I continued to receive weekly reports from my staff. One of them contacted me and told me the good news: It had been hard to identify a solution to dissolve cucurbituril, but they found it by chance. This discovery encouraged me to keep on studying after returning from MIT. Finally, in 1996, I published two papers in the Journal of the American Chemical Society and became the first Korean researcher to have my results featured in Chemical & Engineering News (C&EN) twice in two months’ time. (C&EN is a weekly trade magazine published by the American Chemical Society.) After that, my research results were widely recognized at various conferences. My research was selected as an inventive research task by the Ministry of Science and Technology, and I was given a long-term government grant to continue studying.

Supporting Researchers

Economic conditions for researchers in Korea have improved greatly; researchers now have sufficient funds and equipment for their studies. I think it is time we promoted the importance of idea and passion. It is important to provide an environment where young researchers can do the research they want with long-term goals in view. Innovative research studies are possible only when new areas are ventured into boldly. Researchers focusing too much on short-term results cannot achieve such advances. If research funds are provided based on short-term achievements, and promotion or tenure is determined by these, new researchers will study only the subjects that can enable short-term results, and they will not be inspired to challenge themselves with new areas with unknown potential. Discussions on who will win Nobel Prizes, and when, should stop. Instead, fundamental sciences should be supported more solidly. I believe the environment will help and motivate researchers to walk their own ways and freely produce research results.

Advice to Young Researchers

I would like to ask young researchers to dare to study new areas that others have not, instead of seeking an easy way. When you study a difficult subject, you may tend to compare your results with those of your peers, which can be frustrating. Developing a new area is a high-risk, high-return field. The deeper your frustration is, the more fruitful your success will be. Note, however, that you have to consider various possibilities as well. Therefore, entertain big dreams and make daring challenges, but also have a strategy and keep your risk diversified. While pursuing your main area, please find other possibilities for tangible results with lower risks.

See the 2016 Highly Cited Researchers