CUHK Passions and Pursuits

types of such biomimetic scaffold. The first is electrospun nanofibres which are made by spraying a polymer solution, consisting of FDA- approved resorbable biomaterials, in a high electric field, to produce noodle-like threads, though with nano-scale dimensions. The stem cells are then seeded into a scaffold of such nanofibres. The cells would cling to and interact with this nanofibrous biomaterial scaffold, developing into an engineered tissue. The second method is to seed the stem cells into a polymer solution that can be crosslinked with light to produce a hydrogel structure with the use of Projection Stereolithography (PSL) 3D printing technique. This method has the advantage that the cells are readily embedded inside the hydrogel structures which may be custom-fabricated to different shapes and sizes. Lastly, the stem cell-seeded scaffold is placed in a bioreactor, much like an oven or incubator, into which nutrients are fed to simulate the inside of a living organism. The substance incubated in a horizontal axis rotating bioreactor for seven weeks results in a tissue structure that resembles natural joint cartilage, with 75% of its hardness. The replacement cartilage thus engineered has been successfully tested on animals such as rabbits, pigs, goats. To further exploit the technology and extend its application on human beings, Professor Tuan has developed the first ‘microJoint’, a 3D replica of the human joint using a microbioreactor platform to cultivate multiple tissues that make up the joint, which can be used to study and screen for potential therapeutic agents for osteoarthritis. This approach significantly enhances the prospect of identifying and developing drugs and treatment for osteoarthritis. c c Cells adhere to nanofibrous scaffold c c Projection Stereolithography (PSL) 3D printing c c Hydrogel Fabricated by PSL c c Microbioreactor for microJoint chip—first prototype 43