n Main Research Interests
Professor Huo’s group mainly focuses on the following research directions. Aiming at sports training or rehabilitation therapy, they developed the technologies of motion capture, posture recognition, human dynamics analysis and physiological parameter monitoring. Aiming at the application of exercise-promoting human health, they studied on the issues such as osteoporosis and stress-induced bone injury, so as to clarify the mechanism of mechanotransduction in cells, cell-cell and cell-matrix interaction during force-induced bone reconstruction at different scales. Aiming at the development and growth of biological tissues, they developed some experimental techniques and theoretical models of cell mechanics to elucidate the sensing and transmission mechanisms of stem cells to their surrounding mechanical environment.
Figure 1. Main research direction of the research group
n Main Academic Achievements
1. Key technologies of training equipment for ice and snow sports
In 2018, Prof. Huo took charge of the project, “Research and Demonstration of Key Technologies of National Scientific Training Base” from the Ministry of Science and Technology. During the past four years, they developed the technologies such as kinematics, dynamics, physiological function monitoring and analysis, and established the biomechanical models of skeletal muscle and the corresponding analytical methods. In addition, the human dynamics analysis method was coupled with aerodynamic analysis. Finally, they constructed the intelligent training management system of winter sports, 3D testing and scene reproduction system with laser technique, high-speed ejection device of human body, ski-simulating machine with multi-degree of freedom and other large-scale training auxiliary equipment. The above technologies have been successfully applied to the preparation training of the national teams of ski jumping, freestyle skiing, bobsleigh, skeleton, speed skating and alpine skiing for Beijing 2022 Olympic Game. The achievements were displayed in the National Alpine Skiing Center and the China Science and Technology Museum. In 2021, Prof. Huo was awarded as “Chinese Scientist for Ice and Snow Sports” by the General Administration of Sport (18 in total, 14 in China). In January 2022, he won the first-class prize in the 6th China Innovation Challenge and the 5th Zhongguancun Emerging Field Special Competition. Under his guiding, his graduate students won the special prize of “High-tech Winter Olympics” in the 11th “Challenge Cup” extracurricular academic scientific and technological works competition for college students in Beijing, the second prize of the 7th China International “Internet plus” Innovation and Entrepreneurship Competition of College Students (Beijing Zone), the third prize of Excellent Entrepreneurial Team of College Students in Beijing in 2021.
Figure 2. Intelligent management system for the freestyle ski platform
2.A new mechanism of human motion regulating the evolution of bone structure
Wolff's Law is a clinical observation about the phenomenon that the structure of bone tissue can adapt to the changes of external mechanical loading. It is the critical problem to prevent and treat orthopedic injuries and diseases and optimize the rehabilitation programs of human sports. Although it has been recognized in recent years that mechanical stimuli ultimately regulate the structure of bone tissue by influencing the biological behavior of bone cells, the regulatory mechanism remains to be clarified. Since 2006, Prof. Huo began to study the in vivo mechanical microenvironment around bone cells, through the in vitro experiments investigating the biological response and molecular mechanism of cells. The numerical simulation of bone structure evolution under mechanical stimulation and animal experiments were performed. Through the long-term research, they obtained some important achievements, i.e. that osteoclast precursors have the unique ability of sensing the gradient of fluid shear stress (FSS) and migrate toward the region with low FSS; adhesion morphology of multiple osteoclasts affects the cell-matrix interaction and the expansion direction of bone resorption area; osteocytes are more sensitive to flow stimulation comparing with osteoblasts, indicating that they are the main receptor for mechanical stimulation in bone. The further studies of animal experiments and numerical simulation show that the bone structure evolution predicted by the above theory coincides with that experimentally observed phenomenon, which may finally provide a new mechanism of bone structure evolution under mechanical stimulation. Prof. Huo has published more than 50 papers and one book in this field.
Figure 3. Osteoclast precursors have the unique ability to sense the FSS gradient and migrate toward the region with low fluid shear stress
Figure 4. The evolution of trabecular bone considering the biomechanical behavior of osteoblasts and osteoclasts under FSS.
3. The differentiation fates of stem cells under adhesion mechanics
The factors regulating the biological behaviors of stem cells that participate in the development and reconstruction of biological tissues are very important in the field of life sciences. One of the critical issues in tissue engineering is to design the surface of scaffold materials to facilitate the adhesion, growth and differentiation of stem cells. Prof. Huo’s group found that the adhesion circularity of individual mesenchymal stem cells determines their differentiation fates. When studying osteoclast precursors, they found that the spreading shape of cell monolayer regulates the mechanical state in cell monolayer and finally determines cell fusion and differentiation. The above studies are helpful for elucidating the mechanism of development process of biological tissue and for optimizing the surface morphology of scaffold materials in the field of tissue engineering.
Figure 5. Compared to the osteoclast precursors at the edge of cell monolayer, those cells in the middle area tended to fuse into multinucleated osteoclasts, and this phenomenon can be used to predict the location and direction of bone resorption area