[Osteogenesis of human adipose-derived mesenchymal stem cells-biomaterial mixture in vivo after 3D bio-printing].

OBJECTIVE

To construct human adipose-derived mesenchymal stem cells (hASCs)-biomaterial mixture 3D bio-printing body and detect its osteogenesis in vivo, and to establish a guideline of osteogenesis in vivo by use of 3D bio-printing technology preliminarily.

METHODS

P4 hASCs were used as seed cells, whose osteogenic potential in vitro was tested by alkaline phosphatase (ALP) staining and alizarin red staining after 14 d of osteogenic induction. The cells were added into 20 g/L sodium alginate and 80 g/L gelatin mixture (cell density was 1 × 10(6)/mL), and the cell-sodium alginate-gelatin mixture was printed by Bioplotter 3D bio-printer (Envision company, Germany), in which the cells'survival rate was detected by live- dead cell double fluorescence staining. Next, the printing body was osteogenically induced for 1 week to gain the experimental group; and the sodium alginate-gelatin mixture without cells was also printed to gain the control group. Both the experimental group and the control group were implanted into the back of the nude mice. After 6 weeks of implantation, the samples were collected, HE staining, Masson staining, immunohistochemical staining and Inveon Micro CT test were preformed to analyze their osteogenic capability.

RESULTS

The cells'survival rate was 89%± 2% after printing. Six weeks after implantation, the samples of the control group were mostly degraded, whose shape was irregular and gel-like; the samples of the experimental group kept their original size and their texture was tough. HE staining and Masson staining showed that the bone-like tissue and vessel in-growth could be observed in the experimental group 6 weeks after implantation, immunohistochemical staining showed that the result of osteocalcin was positive, and Micro CT results showed that samples of the experimental group had a higher density and the new bone volume was 18% ± 1%.

CONCLUSION

hASCs -biomaterial mixture 3D bio-printing body has capability of ectopic bone formation in nude mice, and it is feasible to apply cells-biomaterial mixture 3D bio-printing technology in the area of bone formation in vivo.