Polysaccharides immobilized in polypyrrole matrices are able to induce osteogenic differentiation in mouse mesenchymal stem cells

Bone marrow mesenchymal stem cells (MSCs) have attracted considerable interest due to their ability to differentiate and contribute to the regeneration of mesenchymal tissues. The present study illustrates that the proper immobilization of heparin (Hep) and hyaluronic acid (HA) into a polypyrrole (PPy) matrix by electropolymerization results in an optimal interface for MSC differentiation towards osteoblast lineage. The obtained thin films showed good thermal stability, hydrophilicity and slow controlled polysaccharide release. The in vitro tests showed the main role of the interface chemical composition. Indeed, PPyHep and PPyHA thin films were able to induce osteogenic differentiation as determined by levels of specific early osteogenic markers (Runx2 and osterix) even in the absence of differentiating medium. Increased levels of ALP and Alizarin red staining, both indicating mineralization processes, confirmed the presence of mature osteoblasts.