Introduction to DOFLA and Bioimaging
Introduction to DOFLA and Bioimaging
  • Professor Chang Young-tae
  • 승인 2017.09.20 07:23
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One of the most important recent technologies in biological study is bioimaging: the visualization of a biological system without sectioning or killing the organism. X-ray CT or MRI is a typical example of bioimaging fully applicable to the human body. As the usual resolution of X-ray and MRI is in mm range, if the sample is smaller than mm size (such as cells, 1-100 micrometer size), optical imaging is the common alternative option. Fluorescence has been the most popular optical method due to its high sensitivity and universal applicability.
The cell is the identity unit of all life forms and each cell represents a unique biological complex system. Discrimination of cell identity is the basis of the understanding for cell function and its role in the whole body. If you want see a specific one cell type, you may need to develop selective sensors or probes for the specific cell. This usually requires a careful elucidation of a unique biomarker for the cell (usually protein) and design of the binding partner (probe). If you do not have a good biomarker, you cannot design the partner. Nature handles this problem by combinatorial synthesis and screening of antibody. When our body has an invader (antigen), there is no time to figure out what they look like. Our body produce millions of antibodies and screen to find the best binder to the antigen. Once a good binder is found, it is amplified to neutralize and wipe out the antigen from our body.
We took a similar approach for the probe development. Rather than design, we made a diverse sets of fluorescent molecules (which is called as library; antibody is biological library) and then screened them against certain cell types to find out the specific probe for the cell. This is called the Diversity Oriented Fluorescence Library Approach (DOFLA). So far, we have built the biggest collection of fluorescent libraries in the world and have demonstrated unprecedented cell type specific probes, including stem cells, neuron, pancreatic islet cells and macrophages. Compared to the conventional design approach, DOFLA has proved much faster and more versatile to any cell types. Utilizing this accumulated experience, I am dreaming to distinguish all the cell types in the human body, and want to establish a unique functional Human Cell Atlas Center at POSTECH. Also, I dream that we can make a sensor platform for everything we want to detect, from any new virus attacks to any funny material in your drink, i.e. a sensor for everything! The sensors can be important components for a smart home or factory, and the bioimaging probes will solve many of our diseases and helps us lead a healthy life.
I was one of the first batch of students atPOSTECH (87’) and studied for 10 years at POSTECH from BS to PhD including 1.5 years of army service. After that, I moved to US for three years as a post-doc, then got a chance to work at NYU (New York University) as an assistant professor in 2000. In 2001, I survived 9/11 in Manhattan, and spent a total of 7 years in New York, teaching American students and carrying out my first independent research career. My English improved dramatically while teaching and mingling with my students. It was another 10 years in the  US, before I decided to come back to Asia. I was thinking about several possibilities, but finally selected Singapore as my next destination. At the moment, I have a vague feeling that my life cycle is about 10 years in one place. In 2007, Singapore was one of the best research environments with a flood of government investment. I got a dual position at NUS (National University of Singapore) and A-STAR (government supported national research institutes), and could run quite big operation with max 48 members in the group. Singapore’s huge investment for the last 10-20 years in science and technology paid off by putting NUS within the top 10 universities in the world. I guess I contributed a little to that, but I always felt something was missing there. After my third 10-year cycle was almost over, I decided to come back to my home country, and to my alma matar, POSTECH.
It was beautiful May of this year. During the 20 years of my absence, the campus is covered with all green, tall trees. Many of them were shorter than me, when I left the campus. In my time, all the buildings were always shiny, after water washing, but now the buildings are showing there age. Many things are still same and remind me of my old memories, but there are also many new things. Many of my old-day’s clubs were changed into more dynamic dancing clubs! After a super busy one month in Pohang, I had to spend another two months in Singapore to finish up the remaining work there, and then came back to POSTECH in August. Now I feel I regained most of my old memories, and the cheerful spirit of POSTECH. Now I recall I was always energetic and smiling when I was at POSTECH, and that was what I missed when I was abroad during the last 20 years.
My juniors look taller, healthier and more handsome. I got a warning from many of my teachers and friends that they are not the same from my days, in good ways and bad ways. Still, they look lovely to me, especially their unsophisticated styles, which I believe is the purity of the spirit. The biggest lesson I learned in my science career (or life in general) is that good communication is more important than anything else. If scientific curiosity and having a caring mind for others are added, I believe you can be a great scientist and a good human being. I wish I can share my experience with my juniors and could help them to grow in the classroom or anywhere at POSTECH. I dream POSTECH to grow further and further, and become the Mecca of science and technology in Korea and in the world.