Abstract: Objective To constructan indirect co-culture model of dental pulp stem cells(DPSCs) and human umbilical vein endothelial cells(HUVECs), and lay a foundation for the establishment of a new indirect co-culture system that can be used in vivo and in vitro. Methods 5% GelMA30 was configured to explore the optimal parameter of 3D bioprinting and to conduct printable tests. The survival of DPSCs and HUVECs in GelMA30 was detected with live/dead staining. Six co-culture models were constructed: direct co-culture of DPSCs with HUVECs (M), culture of DPSCs(D-D200), culture of HUVECs(H-D200), indirect co-culture of DPSCs with HUVECs(M-D0, M-D200, M-D400). The co-culture of DPSCs with HUVECs was observed by photographing. Results The Pr calculation result was 0.97±0.02, indicating that the structure has good printability. On the seventh day, the viable cell rate of DPSCs and HUVECs was 96.48% and 96.00% respectively, indicating that the cells remained active. The printing of co-culture models in 6 groups was successfully completed. Conclusion Indirect co-culture system of DPSCs and HUVECs can be constructed by 3D bioprinting, which will pave the way for subsequent studies.

Key words: dental pulp stem cells, human umbilical vein endothelial cells, 3D bioprinting, indirect co-culture system