by Anna Blanchfield
This summer, I spent 8 weeks at the University of Tokyo in the Takeuchi Lab conducting research on biohybrid devices. The focus of my project was developing a culture media perfusion device for the culturing of skin cells. Typically, culturing cells is done in a static environment such as a dish or well-plate. Therefore, creating a skin model can take weeks as skin is made up of many different types of cells that must be cultured together. To speed up this process, we can perfuse culture media through cell spheroids, as this method more closely mimics in vivo conditions.
I spent the first 4 weeks learning to culture cells in a static environment and preparing the cells for imaging. To grow cell spheroids, I created a polydimethylsiloxane (PDMS) dish with 300 wells, each well having a diameter of about 500 um. The first cells I seeded were fibroblasts, as fibroblasts are very durable cells and grow quickly. Then I seeded fibroblasts with other types of skin cells, such as keratinocytes and vascular cells. A week after seeding the cells, I would fix them in paraformaldehyde so that they could be imaged. The purpose was to collect preliminary data so that we could compare cell growth in static conditions to the eventual cell growth in the device. During these 4 weeks, I was also reading papers on perfusion devices and drawing designs.
For the final 4 weeks, I focused on 3D-printing and testing devices. I decided to use a gravity-based perfusion device, where the movement of culture media was due to a seesaw-motion. There were two parts of the device design: the two-well structure that the culture media would move between and the porous material in the middle that would hold the cell spheroids and allow for the media to pass through. Developing the two-well structure was simple as it only required 3D printing (Figure 1). Developing the porous material proved to be the difficult part. Based off previous papers, I had planned on mixing PDMS with sugar, curing it, and then washing away the sugar such that only a porous cube remained. However, the sugar always sunk to the bottom, so when cured, it was not distributed equally throughout the PDMS. Even increasing the ratio of sugar to PDMS did not help, as the bottom was always much denser than the top (Figure 2). A uniform distribution and size of pores was required to ensure that all cells would receive the same amount of culture media. Unfortunately, I was unable to develop a uniformly porous cube in my time at UTokyo, but the results of my work will be used to shape future steps in the project. This was my first time working with human cell lines and my first time 3D-printing a design of my own. I know that this experience will be helpful in future scientific endeavors.
However, I think I may have learned the most being outside of the lab. This was my first time coming to Japan and my first time living abroad in another country for an extended period. Before coming, I didn’t speak any Japanese or really know very much about Japanese culture. When I first arrived, it was very difficult. Even just shopping at the grocery store was a major struggle, as I couldn’t read any of the labels or ask anyone for help. It felt very isolating, as it’s already uncommon for Japanese people to casually talk to foreigners, let alone during a global pandemic.
Luckily, it didn’t take long before I started to appreciate the Japanese culture. Everyone I talked to was so polite and once they realized that I didn’t speak Japanese, they would go out of their way to communicate. One of my favorite interactions was at a curry restaurant near my apartment. The owner upon realizing my language barrier, revealed that he spoke fluent English personally explained to me all the menu items. He also gave me free vegetables and a free dessert. He was so excited to talk to a foreigner, since so few have been able to come to Japan these days. I’ve been so grateful for all the connections I’ve made, especially the one made with my mentor Dina Myasnikova. Dina took me out to lunch almost every day and helped introduce me to Japanese cuisine. As someone who is originally from another country but has lived in Japan for seven years, it was great to talk to her about the cultural differences. Dina also connected me to her friend Mack Hagiya, a retired Japanese man who took me on free tours of Kamakura and Hakone. I learned a lot about the history of Japan and temple and shrine etiquette from him. All these connections were extremely rewarding and made this an unforgettable experience.
Overall, I had a great experience conducting research at the University of Tokyo. Not only did I learn hard skills that will help me in future research, but my time alone in Tokyo made me a more confident person. If I can move to another country by myself, I’m capable of anything I set my mind to.