Abstract: Objective To detect the residual bovine serum albumin (BSA) in tissue engineered bone constructed conventionally in vitro byβ-TCP and to investigate new methods to reduce it. Methods Human bone marrow mesenchymal stem cells (BMSCs) were isolated and cultured in vitro. BMSCs of passage 2 were digested, after centrifugation and washing, the washing liquid of the cells was obtained. And BMSCs of passage 2 were inoculated in β-TCP scaffolds and induced osteogenesis in vitro for 2 weeks to construct tissue engineered bone. The tissue engineered bone was rinsed in saline for three times, put in PBS buffer and extracted for 24 hours at 37 ℃ to obtain the extracted liquor. The extracted liquor of scaffold without cells inoculated simultaneously was served as the control. Residual BSA content in the extracted liquor and the washing liquid samples were detected by ELISA, and the change relationship of BSA content with times of washing was observed. Results BSA content in the dilution liquid decreased as washing times increased. The average residual BSA in tissue engineered bone and in scaffold material detected by ELISA was (19.54±6.70) ng and (15.67±5.49) ng respectively, which was normalized as (0.656±0.213) ng/mg and (0.796±0.205) ng/mg, showing no significant difference between two groups (P>0.05, n=10). Conclusion ELISA method is suitable for the detection of the residual BSA in tissue engineered bone. As the scaffold materials absorb BSA more easily than the cells, the residual BSA in tissue engineered bone is still relatively high. Therefore, further studies of reducing BSA residual are still needed.

Key words: Bovine serum albumin, Enzyme-linked immenosorbent assay, Tissue engineered bone, Residual