IAS Scholars

IAS Junior Fellow and Research Assistant Professor of Physics
GUAN Dongshi

Dr. GUAN Dongshi received his PhD in Physics from HKUST in 2016. He was trained as a soft matter physicist, and gradually became involved with interdisciplinary research on biological systems. In his research, he uses the atomic force microscope (AFM) as a microscopic “finger” to detect liquid-air interfaces, soft material surfaces, and living matter such as cells and tissues, to study their mechanical properties and underlying physics. He aims to develop new techniques for studying cellular biophysics, and to gain a better understanding of living matter from the viewpoint of a physicist.

In 2014, Guan was a Visiting Scholar at the Laboratoire Interdisciplinaire de Physique in Grenoble, France. After graduation, he served as a Postdoctoral Fellow in the Department of Physics at HKUST, and subsequently became an IAS Junior Fellow and Research Assistant Professor of the Department of Physics in 2017.

Where Physics Meets Biology

Although science is often taught as if the various disciplines were clearly separate, exciting things can happen when the boundaries blur. The study of soft matter is one emerging field that has received increasing interdisciplinary attention from researchers in physics, chemistry, mechanical engineering, and life science. Living cells, as particular forms of soft material, exhibit unique mechanical properties that are closely related to their activities, functions and health. One remarkable example is cancer cells, which appear to be softer than normal cells.

Accurate measurement of the morphology and viscoelastic (squishy) properties of living cells is thus essential for understanding the microscopic origins of cell mechanics in relation to cell responses and functions. As Guan explains, “A major challenge to the experiments is that the cells are extremely soft and delicate, and are surrounded by a liquid medium.”

To deal with these difficulties, Guan and his colleagues have developed new techniques based on the AFM that enable simultaneous imaging of the surface topography and the viscoelasticity of living cells. This approach can reveal the ways in which the stiffening and softening of a cell is associated with its movement and reproduction. Guan reports that “our noninvasive and ultrasensitive technique opens the door to studying a range of interesting problems in the nano-mechanics of soft matter and the mechanobiology of protein condensates and tissues.”

This year, Guan’s proposal for an experimental study of the volumetric and viscoelastic properties of mitotic cells and their responses to external mechanical cues has been funded by the Hong Kong Research Grants Council. He is collaborating with Prof. TONG Penger and other faculty members from Physics, Chemistry, Life Science and Electronic & Computer Engineering.

\\ Soft and living matter mechanics is the bridge between physical and biological sciences. \\