Text | "China Science News" reporter Gan Xiao
At the beginning of this century, Tang Benzhong led a research team to propose a new concept of aggregation-induced luminescence (AIE) for the first time in the world. This discovery of the Chinese to rewrite the textbook of light physics has opened up a new field of original and leading scientific research in the world, and has won the first prize of the National Natural Science Award. Tang Benzhong was elected as an academician of the Chinese Academy of Sciences in 2009 and transferred from the Hong Kong University of Science and Technology to the dean of the School of Science and Engineering of the Hong Kong University of Chinese Shenzhen in 2021.
In recent years, based on his scientific research experience and perception of exploring new phenomena and new connotations of AIE, Tang Benzhong has advocated the shift from the "molecular theory" based on reductionism to the "aggregate theory" based on holism.
Tang Benzhong Photo provided by the interviewee
Great view on the side of the road
"There are hardly any research topics that develop exactly as intended. Recalling the process of discovering AIE, Tang Benzhong was deeply touched: the beautiful scenery is not on the flat road, but on the side of the rugged path......
Luminescence is the physical process by which matter converts absorbed energy into light radiation. Over the past few hundred years, a photophysical phenomenon known as "aggregate quenching luminescence (ACQ)" has been observed in many luminescence systems.
ACQ refers to the high efficiency of luminescent molecules in dilute solution, but in the concentrated solution or in the aggregate state, their luminescence is weakened or even completely disappeared. The ACQ effect is so widespread that it has become a common knowledge in the field of luminescence research.
Many scientists are working to improve the properties of luminescent materials, prevent molecular aggregation, and avoid the ACQ effect.
The turning point came in 2001. One day, a student in Tang's research group found that the sample point on the thin layer chromatographic plate did not observe the fluorescence emission as expected under the irradiation of the ultraviolet lamp, and after a while, after the solvent volatilized, the "wet point" of the sample became a "dry point", that is, after the material gathered, it emitted bright fluorescence.
The more it gathers, the more it glows? This is the opposite of the ACQ effect. Tang Benzhong did not easily suspect that the students might be mistaken, but keenly believed that this "abnormal" phenomenon was "very interesting".
"If we can prove that ACQ is not necessarily right, it would be a meaningful breakthrough. He said that just as the philosopher of science Popper put forward the "falsificationism", the "confirmation" of bold assumptions and the "falsification" of cautious conjectures both represent the progress of science.
After rigorous design experiments, they confirmed that the phenomenon of "the more you gather, the more you emit light", and named it AIE.
Tang Benzhong told China Science News: "To engage in basic scientific research, we must dare to question, have the courage to falsify, and revise or even overturn widely accepted models and common sense. ”
Enlighten science with philosophy
Tang Benzhong is a philosopher. In his view, science originated from philosophy, and both reflect human perception and awareness of the external world.
In fact, Tang Benzhong has loved literature and art since he was a teenager. He was fond of reading miscellaneous books, which laid the foundation for today's philosophical thinking about science.
In 1977, the national college entrance examination was resumed, and under the inspiration of "learning mathematics, physics and chemistry and realizing modernization", Tang Benzhong embarked on the road of studying chemistry. In 1982, after graduating from South China University of Technology with a major in polymer chemical engineering, he was selected by the Ministry of Education to study for a doctorate degree in polymer synthetic chemistry at Kyoto University in Japan as one of the first batch of publicly-funded international students sent by the mainland after the reform and opening up.
"My supervisor at Kyoto University is an internationally renowned master of polymer synthesis. His mentor was very old and always thought about philosophical questions, which also inspired me. Tang Benzhong recalled.
Tang Benzhong has a deep understanding of the concept of "paradigm". In the 60s of the last century, the American philosopher of science Thomas Kuhn proposed the concept of "paradigm shift" in his book "The Structure of Scientific Revolutions", which had a profound impact on the field of philosophy of science.
"Paradigm" refers to a norm of scientific research, a theoretical framework or basic rule that scientists follow in a certain stage of their exploration of nature. Tang Benzhong believes that the current research of physical science follows the paradigm of "molecular science", which is an epistemology based on reductionist philosophy.
"Under this paradigm, people believe that everything in the world can be 'reduced' to the simplest and most basic tiny particles (or parts), and their laws of motion and behavior can be recognized and described, and the 'whole' is the sum of these 'parts'. Tang Benzhong said that the great success of mechanical reductionism has induced people to expand reductionism to a wide range of fields, even life sciences.
However, in fact, reductionism is increasingly being challenged. Recently, a retired Israeli professor's book, "What is Life: How Chemistry Became Biology?," was placed as bedtime reading at Tang Benzhong's bedside.
In the book, the author points out that at present, people have made significant progress in the field of molecular biology, and understand the chemical structure of biomolecules such as proteins, DNA, RNA, fats, and sugars through reductionism, but they have little understanding of the formation and nature of life.
Tang Benzhong also felt the same way. "For example, the two diametrically opposed phenomena of ACQ and AIE that I am familiar with, the aggregation from single molecules to multiple molecules can produce completely new aggregate materials. Some structures and properties that seem 'impossible' at the molecular level become 'possible' at the aggregate level. He told China Science News, "According to the molecular science paradigm, it is difficult to explain and understand the new structures and properties that emerge from these aggregation processes, and to reveal their formation mechanisms and working mechanisms, which requires the guidance of new philosophical ideas and research paradigms." ”
From molecular theory to aggregate theory
For more than 20 years, Tang Benzhong has been committed to making AIE materials bigger and stronger. As a new material system that is original in China, its derived new technologies and products are expected to break the monopoly of foreign fluorescence detection technology and related products.
Researchers have taken advantage of the special properties of AIE to explore its potential for biodetection. For example, water-soluble AIE motifs do not emit light in aqueous media, but do when they aggregate in diseased tissues such as tumors.
At present, from the breakthrough of original theories to the promotion of industrial applications, Tang Benzhong has led the team to open up almost the entire innovation value chain, and AIE can be seen in many fields such as bioimaging, chemical sensing, optoelectronic devices, information storage, cancer diagnosis and treatment, nanomedicine delivery, and low-carbon city construction.
"We began to think in terms of philosophical 'emergence'. Tang Benzhong said that the ancient sage Lao Tzu's "one life is two, two is three, and three is all things" gave him enlightenment - gradual change causes sudden change, and quantitative change leads to qualitative change.
Based on this thinking, Tang Benzhong proposed the concept of "aggregate science" and called for the shift from the research paradigm of "molecular theory" to "aggregate theory". To this end, he founded a scientific journal called The Aggregate.
"Taken as a whole, there's an infinite amount of room to explore beyond the molecule. The study of aggregates will bring us new models, new hypotheses, new pictures, new theories, new mechanisms, and new channels...... Scientists can work on the fertile soil of the aggregate and explore on this platform. The new knowledge and technologies generated by the study of aggregates will advance science and society. He said.