Social Contributions through Innovative Electrical and Electronic Circuits for Biomimetic Application to the Field of Medical Engineering

I specialize in research related to electrical and electronic circuits (hereinafter, “circuits”).  My recent studies center around Very Large-Scale Integration (VLSI)* designs for biomimetic engineering, with a focus on cochlear and brain functions.

My interest in circuit designs started when I was a teenager, and I became a researcher in the field to pursue basic theory studies. My career came to a significant turning point in 2005, when I participated in an international conference, where I first encountered research endeavors aimed at developing integrated circuits that can substitute for part of the brain’s functions. I thought I could apply my achievements from years of research activities to medical engineering. I was intrigued by this possibility. 

In the medical engineering field, circuit designers have made major contributions to the cochlear implant process. The cochlea is the innermost part of the ear that involves hearing. The organ converts sound information coming from the outer ear to electrical signals to be transmitted to the brain. The cochlear implant process has been developed to produce equivalent functionality by leveraging VLSI technology, with the aim of fixing hearing impairments due to cochlear damage.

Cochlear implant technology is already in practical use, and has advanced to levels that enable normal conversation. The major challenge at present, however, is inadequate sound quality. Therefore, I am working on improving accuracy to provide clearer sound recognition, aiming to achieve the equivalent of the natural hearing function of the inner ear (see Figure 1).

Engineering for the brain poses a more formidable challenge. As the brain is a complex central system, it is difficult to create a single mechanism that can operate as a substitute for the whole system. Thus, current circuit design efforts focus on creating versatile master platforms that allow flexible circuit arrangements to be able to substitute for part of the brain functions. Many such efforts are focusing on the hippocampus, part of the limbic system that plays important roles in the consolidation of new memories and spatial orientation (see Figure 2).

Biomimetic projects targeting hippocampal functions are being promoted worldwide, mainly in the United States. There has been remarkable progress in this research field since 2005, when I was intrigued by presentations on experiments with rats at the international conference. In 2018, notable reports were published on the results of basic experiments aimed at clinical application to repairing damages of the human brain, which showed minimal but significant improvements in the human brain function. 

Related research activities will be spurred toward practical application in the coming years. Given the potential of circuit designs to improve performance, I am pursuing advanced research in anticipation of future demand.

I started to build my career as a researcher at Hosei University. I worked at other universities in the Kansai region for years before returning to my alma mater in 2018.   My laboratory is located on the Koganei Campus, where I studied as a student. The appearance of the campus has changed due to the redevelopment project, including refurbished school buildings. However, I feel that the present students look generally unchanged from those I knew in the past.

The Koganei Campus attracts many inspiring researchers who pursue innovations, exercising their own ingenuity and wisdom. This is possible thanks to Hosei University providing an environment that encourages such academic professionalism. 

Knowledge of electrical and electronic engineering will help develop the biomimetic engineering technology, but it also requires knowledge from other fields. The most essential is anatomical knowledge about the structure of the target organs and their functional mechanisms in relation to nerves and other organ cells. For this purpose, it is vitally important to ensure accessibility to achievements and measurement data from preceding research efforts in the fields of biology and medical science. 

I will bring together knowledge and insights accumulated by many preceding researchers in respective fields of specialization to apply to my studies, aiming to contribute to society.

Successful biomimetic engineering projects can artificially reproduce biological functions. This achievement can be applied not only to medical engineering but also to other fields of science.

In my laboratory, a number of students are working on applied research. 

One such project was to develop an electronic brain for robotic insects. The project designed circuits that can effectively imitate the insect’s brain mechanism to provide six-legged robots with insectile locomotion patterns. 

Other student engaged in a project involved the design and development of gene simulators, intended for gene therapy in the fields of genomic medicine and drug discovery.

The gene simulator reproduces actions of intercellular genes and proteins for the purpose of simulating how medicines will act on specific genes.

In order to produce effective application results that can serve society as practical wisdom, you should engage in robust basic research to build a solid research foundation.  Solid basic knowledge is the key to versatile application development.

In recent years, research activities have been expanding in many countries, especially China and India, a phenomenon that is seemingly overshadowing Japan’s research activities. Going forward, the research sector will become more diversified and internationalized. Given this context, I feel Japan is facing an urgent need to develop competent engineers and researchers to duly demonstrate its potential research capabilities. I hope to play a role in addressing this task.

Very Large Scale Integration (VLSI) is the process of creating an integrated circuit by combining numerous transistors onto a single chip using semiconductor device fabrication processes. The resultant products are called very large scale integrated circuits.