Abstract: BACKGROUND: Platelet-rich plasma is used to promote the proliferation of thin endometrial cells, but there are problems with difficult dose control and sampling. Microfluidic-chips have the advantages of high throughput, low consumption, and simplified operation, providing a new approach to simulate the in vivo microenvironment of endometrial cells. 
OBJECTIVE: To establish a model of promoting endometrial cell proliferation with platelet-rich plasma by the three-channel microfluidic-chip.
METHODS: Platelet-rich plasma was extracted from peripheral venous blood of a female. Human endometrial stromal cells were cultured in serum-free cell media with different concentrations of platelet-rich plasma [0%(control), 0.5%, 1%, and 2%]. Cell migration was detected by scratch test. Cell proliferation was
detected by CCK-8 assay. A microfluidic chip was prepared by using polydimethylsiloxane adhesive. The microfluidic chip was designed with three channels. The middle channel was the extracellular matrix hydrogel channel. Human endometrial stromal cells and platelet-rich plasma channels were found on the left and right sides. There was an area between the three channels that could communicate with each other and realize material exchange. Human endometrial stromal cells (labeled with green fluorescent protein GFP) and serum-free medium containing 0.5% platelet-rich plasma were added to both sides of the experimental group. Human endometrial stromal cells (labeled with green fluorescent protein GFP) and serum-free cell media were added to both sides of the control group. After co-culture for 48 hours, the cell proliferation and migration were observed by Ki67 immunofluorescence staining. 
RESLUTS AND CONCLUSION: (1) The results of cell scratch test and CCK-8 assay showed that compared with the control group, platelet-rich plasma at 0.5%, 1%, and 2% concentrations could promote the migration and proliferation of human endometrial stromal cells (P < 0.05). In addition, the promotion of cell migration and proliferation of platelet-rich plasma with 0.5% concentration was stronger than that of the other two concentrations (P < 0.05). (2) Ki67 immunofluorescence staining showed that compared with the control group, the proliferation and migration abilities of endometrial stromal cells were stronger in the experimental group. (3) The experiment proves that the microenvironment of endometrial cells can be simulated by the three-channel microfluidic chip. At the same time, the system has proven that platelet-rich plasma can significantly promote the proliferation and migration of endometrial stromal cells. 

中国组织工程研究杂志出版内容重点：生物材料；骨生物材料；口腔生物材料；纳米材料；缓释材料；材料相容性；组织工程

Key words: microfluidic-chip, platelet-rich plasma, endometrial stromal cell, endometrium proliferation, migration, extracellular matrix, thin endometrium, endometrial-related disease