Qi Chen (promotion date: 17 December 2009)

Chemistry in block copolymer nanocontainers: Self-assembly, container properties and confined enzymatic reactions

Promotion date: 17. December 2009

Promotor: Prof. Julius Vansco

This thesis describes the preparation and characterization of ‘vesicles’ made from amphiphilic block copolymers, and subsequently their use as nano-containers for the study of enzymatic reactions in atto-liter confined space.

What was the hard part of your thesis project?

It took some time to find the right enzymes to load into the nano-container, and then to look at their kinetics. We tried different things to reach this goal: using diverse materials for the self-assembly of the containers, and trying to find enzymes which were both stable and kinetically slow enough to observe.

What were the main findings after succeeding this difficult step?

The volume created by membrane boundaries of the containers, was found to be related to the catalytic activity of the encapsulated enzymes. This is due to confinement effects, as I call them. There are two aspects in this case: high collision frequencies between the reagents, and a strong interaction between the enzymes and the container wall. This was predicted in previous theoretical studies but not observed experimentally yet.

Did you have applications in mind when studying these reactions?

In the past similar processes have been investigated, because it opens new ways of designing medicine, using these containers as drug carriers. Also diagnostic methods can benefit from a deeper understanding of these processes. I approached the field from a fundamental point of view. By doing so, one can use the build-up knowledge later on in a more practical context.

So, you consider yourself an academic researcher?

Yes, I like the freedom of pursuing my own goals. During the thesis project I learned to define my own project, thanks to Julius Vansco, who helped me a great deal with that. Although fundamental, this subject has a true application potential. That feature, I find very important for my motivation as a researcher.

Did you feel a member of Mesa+?

Yes, very much so. I remember very well when I first came to Mesa+, as a master student of Nanotechnology, six years ago. A lot of professors were present in the introduction meeting, reflecting the multidisciplinary character of the institute. I was very impressed at the time.

Also the research facilities are first class here. But what is most important: the working sphere remains the critical factor of success, in my opinion. Mesa+ must take the open, critical and warm social environment with it in the future.

What are your own future plans?

My preference is always to stay in academic research. Plans to go and work in Singapore are under consideration at the moment. This is a good option for me and my family, since in that case we will be much closer to my home country.