Controlling the interface between bio and nano

Creating new devices by bridging biology and electronics.

"At graduate school at the University of Tokyo, under the guidance of my supervisor Professor Hidefumi Akiyama, I worked on using semiconductor nanostructures to create new lasers. The essential point of a sophisticated laser is the extent to which it can reduce the unevenness of nanostructures. Greater uniformity in structures results in better performance of devices. I applied this idea to the [bio-nano] interface. The first issue I worked on was how to create a stable peptide structure."
Hayamizu pursued the stability and ordered structure of the bio-nano interface, themes that had not been emphasized in previous research. He also focused on observing what kinds of physical phenomena occur on the structure. By doing so, it is possible to observe still-unknown reactions on the surface of solids, such as the relationship between peptides and water or ions in solution, and the action when a voltage is applied. This is expected to advance understanding on the molecular level. Beyond precise interface design, it is possible to envision biosensors that operate completely differently from conventional mechanisms.
"In our lab, we often use the phrase 'imagine that you are a peptide.' In order to observe how peptides behave on the stage of a clean interface, it is necessary to properly set the characters and the stage."
On the interface, the molecules undergo self-assembly and are stable as a whole, reconciling with each other. The research group takes a bird's-eye view of the stage, repeating design and experiments while imagining what kind of scene will unfold. "Conducting this research is like fulfilling the roles of both a producer and director of a drama," explains Hayamizu with a laugh.

"When I was in the second grade of elementary school, my father took me stargazing," recalls Hayamizu. He says that the experience was the beginning of his interest in science and engineering, as well as his perspective and knowledge for overseeing research projects. During his time at the University of Washington, Hayamizu describes that he felt a difference in thinking when working with researchers from other fields. "At that time, I trained myself to apply the concepts of physics in terms of considering matters from a simple perspective. That led me to my current work as a researcher. However, it is said that, in the 21st century, new science will be born by interweaving complex knowledge on matters such as biology into physics. Currently, I am conducting research through my own methods of trial and error."
Living organisms are a treasure trove of knowledge and mechanisms. The fusion of biology and electronics is appealing because skillful utilization will make it possible to create new devices. As a researcher working in this dynamic field, Hayamizu has the motto: "While always being suspicious about whether you hold stereotypes, create a system for accepting new ideas."
"The relationships between people are important and are the true thrill of interdisciplinary collaboration. For example, I was given the opportunity to conduct research at the University of Washington thanks to mediation by Professor Sumio Iijima (Honorary Fellow of the National Institute of Advanced Industrial Science and Technology) during my time at AIST. Thanks to that relationship, we are still collaborating even now."
Furthermore, collaborative research with institutions such as the University of Manchester, RWTH Aachen University, and the Max Planck Institute has expanded because of what Hayamizu learned from Professor Akiyama while at graduate school and through his encounters at AIST. He is also engaging in collaborations with industry. One example is an ultrahigh-sensitivity odor biosensor currently being developed through the Cross-ministerial Strategic Innovation Promotion Program (SIP) operated by the Cabinet Office.
"When considering the increase in inbound tourists during the Olympic Games, companies have proposed the development of social infrastructure to replace quarantine dogs at airports. So we started the project and are working hard to meet their expectations."

Hayamizu applied for the tenure track system at Tokyo Tech when he was at the University of Washington, and became a faculty member. "Around one year after starting research at the University of Washington, I was granted research funding as a Sakigake (PRESTO) researcher, which gave me the opportunity to return to Japan twice a year in order to present results. At that time, I had already learned about the tenure track system. Unfortunately, the Great East Japan Earthquake occurred when I returned to Japan."
Hayamizu returned to America the day after the earthquake. "I felt as if I was fleeing from Japan," he recalls. "In America, I lived a normal life—although heart-wrenching news flowed from Japan on a daily basis. I felt guilty about being in America, and I wanted to do what I could to help Japan. So, I applied for the tenure track system."
Committed to giving back to Japan, Hayamizu is endeavoring to develop unprecedented devices. "In the coming era, infectious diseases like COVID-19 will have a huge impact. The breadth and depth of research fields such as biosensors and the accompanying sense of responsibility will be immeasurable. I feel intense motivation to delve even deeper into the science of solids and liquids, and to further advance my efforts in pursuing new research styles for understanding at the molecular level."

• Department of Materials Science and Engineering, School of Materials and Chemical Technology

Published: December 2020