The purpose of this study was to analyze the interaction be- tween mesenchymal stem cells and novel chitosan/polyester fiber mesh scaffolds, namely their growth patterns and os- teogenic differentiation. This study is a first step for the future development of a bone tissue engineering construct based on the two above referred components.
Scaffolds were obtained by first melt blending chitosan with poly-butylene succinate (PBS) in a proportion of 50% (wt) each, obtaining originally a thermoplastic material containing high amounts of chitosan. This novel melt processable blend was then processed by fiber extrusion. Finally, these fiber structures were knitted into 3D patterns of variable pore size. Human bone mar- row mesenchymal stem cells (MSCs) were seeded on the scaf- folds and cultured for 3 weeks under osteogenic conditions. Af- ter 7, 14 and 21 days samples were collected for further analysis. Cellular viability and proliferation was evaluated by a MTS test. The early differentiation of the cells was screened through the determination of Alkaline Phosphatase (ALP) activity. Finally, the morphology of the cells when in contact with the scaffolds surface was observed by scanning electron microscopy (SEM) and the mineralization content of the elaborated ECM was analysed by energy dispersive spectroscopy (EDS).
Results showed that the tested MSCs were able to reduce MTS, showing increasing metabolic rates with time, and de- noting in this sense a high viability and proliferation profile. Furthermore SEM observation also revelead that cells were able to adhere to the struts of the scaffolds, being able at the same time to bridge between them. Underneath the MSCs multilayer it was possible to detect the elaboration of ECM, that after EDS analysis showed to contain Ca and P, being therefore mineral- ized. This fact clearly shows that cells had undergone an os- teogenic differentiation and were elaborating ECM.
The results of this study showed that novel chitosan/poly- ester fiber meshes scaffolds support the proliferation and os- teogenic differentiation of mesenchymal stem cells on its sur- face in vitro and so might be suitable for being used as scaffolds in tissue engineering related therapies.