Membrane thickness is an important variable in membrane scaffolds: Influence of chitosan membrane structure on the behavior of cells

Cell and tissue responses to polymeric materials are orchestrated in part by the conformations of adsorbed plasma proteins. Thus, the chemical properties of a polymer membrane that govern protein adsorption behavior can play an important role in determining the biological properties of tissue engineered scaffolds derived from that polymer. In this study, we explored the role of membrane thickness as a factor influencing cell adhesion and proliferation on chitosan membranes with and without covalently attached glycosaminoglycans. Rat mesenchymal stem cells (MSCs) cultured on chitosan membranes of various thicknesses demonstrated significantly improved cell adhesion, spreading and proliferation as membrane thickness was increased. Rat hepatocytes displayed increased spreading on the substrate with increasing membrane thickness, similar to MSCs. Increased thickness reduced the overall crystallinity of the membrane, and the data indicate that the improved cellular responses were likely due to enhanced adsorption of serum vitronectin, presumably due to reduced membrane crystallinity. These results demonstrate that membrane thickness is an important design variable that can be manipulated in chitosan-based scaffolds to achieve enhanced cell spreading, proliferation and function.