Comparative Study of Three Copolymer Scaffolds Seeded with Human MSC

Objectives:

In this work we aimed to investigate the attachment and differentiation of human bone marrow mesenchymal stem cells (MSCs) seeded on three types of copolymer scaffolds.

Methods:

The scaffolds were produced by copolymerization of the commonly used L-lactide (PLLA) polymer and the completely amorphous polymer 1,5-dioxepan-2-one (DXO-co-LLA) or caprolactone and L-lactide monomer (CL-co-LLA). PLLA was used as a control. All the scaffolds had a pore size of greater than 90 µm. Human MSCs were seeded on the scaffolds at 150,000 cells/ml density. After 1, 3 and 24 h, cell attachment was examined by cell proliferation assay (WST-1) and analyzed by scanning electron microscopy (SEM) after 1 h, 24 h and 14 days. After 7 and 14 days of incubation, the cells were harvested and total RNA was extracted. The expression of alkaline phosphatase (ALP), Collagen I (Col I) and runt-related transcription factor 2 (RunX2) was quantified by real time RT-PCR.

Results:

Attachment of the cells on the scaffolds was found to increase from 1 to 3 h and to decrease from 3 to 24 h as measured by WST. SEM analysis indicated that MSCs attached to the scaffolds after 3 h and a thin sheet of cell layers covered the scaffolds on day 14. Furthermore, cells had spread well into the pores. The expression of ALP, Col I and Runx2 was found to increase on the control scaffold from 7 to 14 days. Interestingly, a decrease from day 7 to day 14 in the expression of the 3 genes was found on CL and DXO scaffolds.

Conclusion:

Both DXO and CL scaffolds showed a good biocompatibility, and attachment of human MSCs. We suggest therefore that both DXO and CL might be appropriate for bone tissue engineering.

The study is supported by Helse Vest and the Research council of Norway.