Prof. Yokoi, could you provide a summary of your professional research background?

My specialty is ceramic biomaterials. In this field, research and development is carried out for medical applications, such as for artificial bones, artificial joints, dental materials, imaging probes, and cancer treatment. Ceramic biomaterials are widely useful for the treatment of many diseases and injuries, but recently, research on materials also for diagnostic purposes has attracted attention.

Could you provide a summary of your article published in Communications Chemistry for the general reader? What has been your biggest challenge, and how did you overcome it? (If you have any figures, please include them.)

In this paper, we reported the development of fluorescent calcium phosphate materials that can be used not only for the treatment of bone defects but also in diagnostics. I took this photo (Figure, left) in August 2018, when I found this material to have fluorescent properties. Although in this image, it may appear to be nothing more than blue light, I was really excited by the successful synthesis of a material with fluorescent properties. I wanted to investigate the fluorescence characteristics in more detail, but at that time I could do nothing more than take a sample photo using a UV lamp. I showed this photo my co-author, Prof. Ohtsuki, Nagoya University, and he introduced me to Prof. Hara and Prof. Seki who carried out high-level fluorescence measurements (Figure, right). I am truly grateful for my co-researchers, as this work would not have been possible without them.

What wavelengths of light should be absorbed and what colors (emission wavelengths) would be ideal for the practical application as artificial bones?

This is a very important aspect of artificial bone development. There is a wavelength region in which the human body has high transmittance, called the biological window. We need to design our materials so that they can be excited to emit light in that region. For example, a calcium phosphate-based material that can be excited by 800-nm light and emit 1100-nm light would be a promising candidate for artificial bone that can be used both to repair bone defects and to make fluorescence-based diagnoses in the affected area. The materials we have so far do not have this fluorescence characteristic, so we are continuing our work to get closer to this desired result.

How would you bridge the needs of medical doctors to bring this technology to fruition? Also, what would you like to achieve in the future?

The trigger that started the development of artificial bones that are useful for diagnosis was a conversation with a dentist. He emphasized the need for such artificial bones for use in his field. In the future, in parallel with the improvement of fluorescence characteristics, we will proceed with the evaluation of the biological characteristics of our materials. My hope is that a company will be interested in our research and put our materials to use in practical applications. Artificial bones that are useful for diagnosis are not yet available anywhere in the world, so I would like to continue our research toward developing this "world's first".

What made you decide to publish your work in Communications Chemistry, what do you feel in the process from submission to publication, and How was the impact of the work in your field after the publication?

A researcher I knew had a press release of their research results published in Communications Biology, and I also wanted a press release for our research results, so I decided to publish our paper in a sister journal, Communications Chemistry. The reviewers who understood my research very well gave us appropriate comments, and I think that the quality of our paper improved during the peer review process. However, it was a pity that we were unable to perform additional experiments due to the spread of COVID-19. After the paper was published, we issued a press release as planned, and the results were fortunately taken up in a newspaper. I think that this paper was particularly well received in our society and in my research field in comparison to my previous papers.

What kind of things do you do to come up with a research theme? Or, what do you keep in mind every day to plan a new research theme?

When listening to presentations of seemingly little relevance to my own research at a conference, I sometimes come up with the idea that the presented research concept might also be incorporated into my research. Even if the concept I want to integrate is similar to what has already been studied, sometimes there can be considerable novelty or value added just by changing the research field. So, I consciously try to listen to presentations outside the field of my specialization.

Prof. Taishi Yokoi is at the Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University.  

Interview by Prof. Satoshi Honda (University of Tokyo), External Board Member, Communications Chemistry.