Behaviour and ultrastructure of human bone marrow-derived mesenchymal stem cells immobilised in alginate-poly-l-lysine-alginate microcapsules.

Human bone marrow mesenchymal stem cells (hBM-MSCs) show a great promise for the treatment of a variety of diseases. Despite the previous trials to encapsulate hBM-MSCs in alginate-poly-l-lysine-alginate (APA) systems, the various changes that follow immobilisation have not been ascertained yet. Determine the various consequences derived from entrapment on cell behaviour, putting special emphasis on the ultrastructure. hBM-MSCs were immobilised in APA microcapsules to further characterise their viability, metabolic activity, proliferation, VEGF-secretability, and morphology. The VEGF produced by monolayer hBM-MSCs increased significantly 1 d post-encapsulation, and was maintained for at least 4  weeks. TEM imaging of cells revealed well preserved ultrastructure indicating protein synthesis and high metabolic activity. Although APA microencapsulation did not support 100% of fully viable hBM-MSCs for long-term cultures, it was conceived to enhance both VEGF secretion and metabolic activity while not losing their stemness characteristics.