Alginate-chitosan PEC scaffolds: A useful tool for soft tissues cell therapy

In this study we evaluate macroporous scaffolds made of alginate-chitosan polyelectrolyte complexes (PEC) as tools to optimize the results of soft tissues cell therapy. Cell therapy using mesenchymal stem cells (MSC) has become attractive for tissue repair and regeneration in a number of acute and chronic injuries. Unfortunately their low retention and/or survival after injection limit their beneficial effects. A biomaterial-assisted implantation, providing cells a three-dimensional (3D) microenvironment is a promising strategy. To this purpose, we designed a family of PEC scaffolds, and studied if they could meet the requirement of such application. Xray tomography showed that all PEC scaffolds present an interconnected macroporosity, and both rheology and tensile measurements reveal optimized mechanical properties (higher storage moduli and Young moduli) compared to alginate reference scaffolds. In vitro assays demonstrated their ability to allow MSC retention (higher than 90%), long-term viability and FGF2 secretion. Then, we used a skeletal muscle implantation model to assess the biological response to scaffolds graft, and showed that they support in vivo vascular formation within the implant-derived tissue. The combination of alginate/chitosan PEC scaffolds architecture and angiogenic potential make them appear as interesting tools to optimize MSC therapy results in soft tissues.