It mainly pre-constructs a biologically active implant in vitro by adopting living functional cells and scaffold materials for cells to carry out life activities, and then implants it into the body, in order to repair tissue defects as well as replace all or part of functions of tissues and organs for the purpose of improving the quality of life and prolonging life activities. 

The regulatory mechanism of stem-cell targeted differentiation. 

Cell division and growth regulation. 

Environmental factors affecting the cultivation in vitro of cells.