Department of Materials Engineering
Associate Professor Hirotaka Ejima[CV]
Dec.2016 – present
Associate Professor, Department of Materials Engineering,
The University of Tokyo2011
Ph.D., (Chemistry & Biotechnology), Graduate School of Engineering,
The University of Tokyo[motto]“Live life in such a way that you feel you moved in the best direction.”
These are words from Makoto Fujita, Professor at the University of Tokyo’s Department of Applied Chemistry. A lot of the choices we make in life
don’t have the results we expect, but I think we can live fulfilling lives by thinking positively and giving our best effort, no matter thecircumstances.

Creating New Materials by Learning from Organisms
I have three primary research focuses. The first is selfhealing polymers. When living things are damaged, they areable to heal naturally. If artificial materials were able to selfrepair in the same way, it would be useful. My second research
focus is underwater adhesive polymers. Though adhesives arewidely used today, they often fail to stick in wet environments.
To address this problem, we take inspiration from shellfish(which adhere firmly to rocks in the sea). We work to imitate
the structures of these organisms to help us develop adhesivematerials that work well underwater. My third research focus iscell coating. There’s a type of unicellular organism that createsa shell around itself and begins hibernating if exposed to stresssuch as UV rays or dry conditions. When favorable conditions
return, the organism breaks down the shell and begins growing.
We are researching whether it’s possible to create shells likethese artificially.
Environmental and Medical Applications
A recent news topic was the banning of plastic straws
in cafes and restaurants. This ban was enacted because microplastics—tiny fragments of waste plastic—cause marine
pollution. If self-healing polymers were available, however,plastics would have longer lifespans and would be moredifficult to break down (meaning they would not deteriorate
into tiny fragments). I believe that this technology cancontribute to making sustainable societies.
I also think about the medical applications of adhesivepolymers intended for underwater use. For example, there aretimes when medical professionals would like to use adhesives
to repair cuts in skin or internal organs. The inside of thehuman body is wet, similar to underwater environments. We
aim to develop adhesives that can be used to address theseconditions.
Cell coating would enable us to transport cells suchas iPS cells while preserving their qualities. I believe this could
contribute to developments in regenerative medicine.

Fig. Underwater adhesive took inspiration from marine life
Pursuing my Uniqueness
When I was an undergraduate student at theDepartment of Chemistry in the School of Science, I researched
GFP (green fluorescent protein) cell imaging. Professor OsamuShimomura was awarded the Nobel Prize for his work in thisfield. The professor in the laboratory I belonged to retired, sofor my master’s I moved to the Department of Chemistry &Biotechnology at the School of Engineering, where I studied
polymers yielded by bacteria.
I had aspired to be a researcher since I was anundergraduate student because research was really interestingfor me, but when I looked at the incredible teachers andmentors in my laboratory, I wasn’t sure if it was something I
could truly do myself. What I finally realized was that myexperiences working in different laboratories (for my bachelor’sand master’s coursework) and studying two different fields
gave me a unique strength. I thought that if I pursued my own
uniqueness, I would be able to find my own way as a researcher.
After completing my PhD, I studied drug delivery
systems (systems for delivering medicine within the body) as a
postdoctoral fellow at the University of Melbourne. Althoughdifferent from my previous work, I found the field ofpharmacology very interesting. Furthermore, through studying
abroad I learned about the differences between Japan andother countries, which really inspired me. I hope you broaden
your horizons by studying abroad and interacting withinternational students.