Newsletter No. 531

successfully tested on animals such as pigs and goats. To extend the trials on human beings, Professor Tuan has developed the first ‘microJoint’, a 3D replica of the human joint using a microbioreactor platform (Picture 4), which can be used to study and screen for potential therapeutic agents for osteoarthritis. The prospect of developing drugs and treatment for osteoarthritis in future is not as bleak as in the present. Professor Tuan's interest in the bone dates back to his doctoral student days when he observed that while the egg appears to be all softness and no bone, the chicken thus hatched has a normal skeleton frame. The young Tuan was intrigued by the question: how could something seemingly come of nothing? He did his PhD dissertation on this problem and found that the calcium for the bone of the chicken comes from a thin membrane lining the inside of the eggshell called the chlorioallantoic membrane. This can be demonstrated by incubating a chicken embryo in a no-shell environ. The chicken thus hatched would have serious calcium deficiency and show signs of embryonic rickets. Under Professor Tuan’s leadership, stem cell and regeneration research at CUHK has combined and leveraged on a number of disciplines and institutes. Professor Tuan’s scientific innovation may prompt the mythical Sphinx to rephrase her riddle: what is the creature that walks with four legs in the morning, two at the noon-time, and still two in the evening? T.C. I n Greek mythology, the punishment Prometheus gets for stealing fire for humanity is the daily torture of having his liver eaten up by an eagle. A new liver grows back in the next morning so that the torture can repeat for the new day, and the next ad infinitum. A human organ that regenerates itself exists only in myths. That is, until regenerative medicine came along. Regenerative medicine is the branch of modern biomedical technology that aims to repair or regenerate diseased or damaged tissues or organs of the human body. It encompasses the development of medical devices or artificial organs, tissue engineering, biomaterials, cellular therapies, and clinical translation. Prof. Rocky S. Tuan , Vice-Chancellor and President and Lee Quo Wei and Lee Yick Hoi Lun Professor of Tissue Engineering and Regenerative Medicine of CUHK, is a world-renowned biomedical scientist specializing in musculoskeletal biology and tissue regeneration. His seminal work on musculoskeletal tissues has scripted an important chapter in the big book of regenerative medicine. There are over 200 bones in a human adult. They serve two major functions, namely, weight-bearing and locomotion. The proper functioning of the bones and the joints ensure that human beings can carry on with their daily activities. Bones and joints, however, get damaged through injuries or degenerate with age and the process is irreversible. Take osteoarthritis, for example. The malaise, due to the breakdown of the joint cartilage and the underlying bone, affects 10% to 15% of the population over 60. It is estimated that 130 million people would be affected by it by 2050. And there’s no cure for it. Like mending a pothole in the ground which requires concrete or asphalt as the filling material, the first step is to find the material to replace the lost or damaged cartilage. In this case, the raw material is human stem cells which can be found in many parts of the human body such as baby teeth and the umbilical cord. Stem cells are ideal material because they have self-renewing power and the potential, when planted in a new environment, to develop the properties or functions relevant in that environment. It is preferable that the stem cells come from the same person in need of a repaired or renewed part. Second, a mould or scaffold is needed for the cells to bind with and merge in. Professor Tuan had pioneered two types of such biomimetic scaffold. The first is electrospun nanofibres which are made by dripping polymer solution, consisting of FDA-approved resorbable biomaterials, through electric currents which would, in the right mix of other atmospheric conditions, yield noodle-like threads, though on a nano-scale. The stem cells are then seeded into a scaffold of such nanofibres. The cells would cling to and interact with this nanofibrous scaffold turning the whole into a biomaterial fit for the purpose (Picture 1). The second method is to dip the stem cells into the polymer solution and fabricate hydrogel pellets with the use of projection stereolithography (PSL) 3D printing technique. This method has the advantage that the hydrogel pellets may be tailored to different shape and size requirements (Picture 2). Lastly, the scaffold is put in a bioreactor, much like an oven or incubator, into which nutrients and oxygen are fed to simulate the inside of a living organism. In one experiment, the substance that had been incubated in a horizontal axis rotating bioreactor (Picture 3) for seven weeks resembles the natural joint cartilage in most aspects with 75% of its hardness. The replacement cartilage thus engineered has been 圖三:橫軸旋轉生物反應器 Picture 3: Horizontal axis rotating bioreactor 圖四:微關節晶片 Picture 4: Bioreactor for microJoint chip—first prototype 中大五十五周年 公開講座 CUHK 55th Anniversary ‘The Pursuit of Wisdom’ Public Lecture Series 為慶祝五十五周年,中大舉辦「智 慧的探索」公開講座,匯萃中大傑 出學人的知識與經驗,傳承智慧。 八場講座於鄭裕彤樓一號演講廳舉 行,涵蓋轉化醫學、人工智能、糧食 與永續農業、宇宙與物理、歷史和 心理學等範疇。段校長於1月11日主 講的「再生醫學的前途與挑戰」為 首場講座,其餘講座詳情如下: To celebrate the 55th anniversary of CUHK, the University launches ‘The Pursuit of Wisdom’ Public Lecture Series which amasses the wisdom, strength and distinction of CUHK experts from across different disciplines and disseminates these in the community. Held at Lecture Theatre One of Cheng Yu Tung Building, the eight lectures encompass translational medicine, artificial intelligence, food supply and sustainable agriculture, physics and the universe as well as history and psychology. The lecture delivered by Vice-Chancellor Prof. Rocky S. Tuan on 11 January titled ‘Regenerative Medicine: Promises and Challenges’ was the first in the series. Details of the remaining lectures are as follows: 日期 Date (5:00 – 6:30 pm) 講者 Speaker 講題 Topic 15.2.2019 盧煜明教授 Prof. Dennis Lo 科研的挑戰與樂趣 The Joys and Challenges of Scientific Research 1.4.2019 林漢明教授 Prof. Lam Hon-ming 大豆研究:一段從實驗室到農田科研之旅 Soybean Research: A Journey from Laboratory to Field 24.5.2019 朱明中教授 Prof. Chu Ming-chung 宇宙的美好缺憾 Beautiful Asymmetries in the Universe 3.6.2019 蒙美玲教授 Prof. Helen Meng 懂聽懂說的人工智能如何改善人類的學習及生活 Artificial Intelligence for Speaking and Listening for Learning and Well-being 9.9.2019 科大衛教授 Prof. David Faure 孝道與產業:為甚麼「孝」有助商業發展? Filial Piety and Business Enterprise: Why is Filial Piety Good for Business ? 23.9.2019 趙志裕教授 Prof. Chiu Chi-yue 心想事成:美滿人生心理學 Mindset and Success: The Psychology of a Flourished Life 14.10.2019 莫樹錦教授 Prof. Tony Mok 待定 To be announced 03 # 5 3 1 | 1 9 . 0 1 . 2 0 1 9