Tang Benzhong, Interviewee Image Provided
By Gan Xiao, Reporter, This Newspaper
At the beginning of this century, Tang Benzhong and his research team first proposed the concept of Aggregation-Induced Emission (AIE) internationally. This groundbreaking discovery by a Chinese researcher reshaped the landscape of optical physics, paving the way for a new field of original and leading scientific research. Tang's work earned him the First Prize of the National Natural Science Award. Tang Benzhong was elected as an academician of the Chinese Academy of Sciences in 2009. In 2021, he transitioned from the Hong Kong University of Science and Technology to become the Dean of the Faculty of Science and Engineering at the Chinese University of Hong Kong (Shenzhen).
In recent years, based on his research experiences and insights into exploring new phenomena and implications of AIE, Tang Benzhong advocates for a shift in the research paradigm from the reductionism-based "molecular paradigm" to the holism-based "aggregates paradigm."
"Almost no research topic develops exactly as expected," recalls Tang Benzhong about the process of discovering AIE. He deeply feels that beauty lies not on the smooth road but along the rugged path.
Luminescence is the physical process by which a substance converts absorbed energy into light radiation. For hundreds of years, scientists have observed a phenomenon known as "Aggregation Caused Quenching (ACQ)" in many luminescent systems. ACQ refers to the phenomenon where luminescent molecules efficiently emit light in dilute solutions but exhibit weakened or even completely diminished luminescence in concentrated solutions or aggregated states. ACQ effect is widely known in the field of luminescence research.
Many scientists have endeavored to improve the performance of luminescent materials by preventing molecular aggregation and avoiding ACQ effect.
The turning point came in 2001. One day, a student in Tang Benzhong's research group found during an experiment that the sample dots on a thin-layer chromatography plate did not emit fluorescence under UV light as expected; after a while, when the solvent evaporated, the "wet spots" turned into "dry spots," indicating that the material emitted bright fluorescence after aggregation.
The more aggregation, the more luminescence? This phenomenon was diametrically opposite to the ACQ effect. Tang Benzhong did not easily suspect that the student might be mistaken; instead, he keenly considered this "anomalous" phenomenon "very interesting."
"If we can prove that ACQ is not always true, it would be a meaningful breakthrough," he said, likening it to the "falsificationism" proposed by philosopher Karl Popper, where bold hypotheses of "confirmation" and cautious conjectures of "falsification" both represent scientific progress.
After rigorously designed experiments, they confirmed the existence of the phenomenon of "the more aggregation, the more luminescence" and named it AIE.
Tang Benzhong told China Science Daily, "Engaging in basic scientific research requires daring to question, courage to falsify, and the willingness to revise or even overthrow widely accepted models and common sense."
Enlightening Science with Philosophy
Tang Benzhong is a lover of philosophy. In his view, science originates from philosophy, and both reflect human perception and understanding of the external world.
In fact, Tang Benzhong has loved literature and art since his youth. His penchant for eclectic reading laid the foundation for his current philosophical approach to scientific issues.
In 1977, with the country's resumption of the college entrance examination and the call for "mastering mathematics, physics, and chemistry to achieve modernization," Tang Benzhong embarked on the path of studying chemistry. In 1982, after graduating from the Polymer Chemistry Department of South China University of Technology with high scores, he became one of the first group of publicly funded overseas students sent by the Ministry of Education of China after the reform and opening up, and was selected to study for a Ph.D. in Polymer Synthetic Chemistry at Kyoto University in Japan.
"My supervisor at Kyoto University was an internationally renowned master of polymer synthesis. He was very old and often contemplated philosophical questions, which also inspired me," Tang Benzhong recalled.
Tang Benzhong has a deep understanding of the concept of "paradigm." In the 1960s, 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.
"A paradigm refers to a norm of scientific research, which is a theoretical framework or basic rules that scientists adhere to in exploring the natural world at a certain stage," Tang Benzhong explained. He believes that the current research in material science follows the "molecular science" paradigm, 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 particles (or parts), and their laws of motion and behavior can be understood and described, while the 'whole' is the sum of these 'parts'," Tang Benzhong said, the great success of mechanical reductionism led people to widely extend reductionism to various fields, even life sciences.
However, what is the reality? Reductionism is increasingly being challenged. Recently, a book by a retired Israeli professor titled What is Life: How Chemistry Becomes Biology? was placed on Tang Benzhong's bedside as bedtime reading.
The author pointed out in the book that currently, significant progress has been made in the field of molecular biology, and through reductionism, people have understood the chemical structures of biological molecules such as proteins, DNA, RNA, lipids, and sugars, but know little about the formation and essence of life, feeling a bit like "blind men feeling the elephant."
Tang Benzhong feels the same way. "Take the two completely opposite phenomena of ACQ and AIE that I am familiar with, for example. From single molecules to multi-molecular aggregation, entirely new aggregate materials can be produced. Some structures and properties that seem 'impossible' at the molecular level become 'possible' at the aggregate level," he told China Science Daily, "according to the molecular science paradigm, it is difficult to explain and understand these emerging new structures and properties during aggregation and reveal their formation mechanisms and working principles, which requires guidance from new philosophical ideas and research paradigms."
From Molecularism to Aggregatism
For more than 20 years, Tang Benzhong has been committed to the scaling up and strengthening of AIE materials. As a domestically originated new material system in China, its derivative new technologies and products are expected to break the monopoly of foreign countries on fluorescent detection technology and related products.
Researchers have exploited the special properties of AIE to explore its potential applications in biometric detection. For example, water-soluble AIE moieties do not emit light in a water medium but luminesce after aggregation in tissues with conditions like tumors.
Currently, from the breakthrough of original theory to the promotion of industrial applications, Tang Benzhong has led the team to almost establish the entire innovation value chain. The presence of AIE can be seen in many fields such as biomedical imaging, chemical sensing, optoelectronic devices, information storage, cancer diagnosis and treatment, nanomedicine delivery, and low-carbon city construction. "We're starting to approach problems through the philosophical concept of 'emergence,'" said Tang Benzong, drawing inspiration from the ancient Chinese philosopher Laozi's idea of "one gives birth to two, two gives birth to three, three gives birth to all things"—the notion that gradual changes lead to sudden transformations, and quantitative shifts result in qualitative changes.
Building upon this perspective, Tang Benzong introduces the concept of "collective science," advocating a shift from the paradigm of "molecularism" to that of "collectivism" in research. To this end, he has founded a scientific journal called Collective.
"Looking at the whole, there's infinite exploratory space beyond molecules. Researching collectives will bring us new models, hypotheses, perspectives, theories, mechanisms, pathways... Scientists can cultivate and explore this fertile ground of collectives, forging ahead on this platform. The new knowledge and technologies generated from collective research will drive scientific progress and social development," he remarked.
Source: China Science Daily, 2024-03-05, Front Page
