Hyaluronan and self-assembling peptides as building blocks to reconstruct the extracellular environment in skin tissue

Self-assembling bioactive membranes, incorporating hyaluronan, a structural component of the skin extracellular matrix (ECM), and peptide amphiphiles presenting biochemical signals, are proposed in this work for recapitulating some aspects of the skin tissue microenvironment. In the herein presented strategy, the availability of cell-adhesion ligands (0-50% RGDS epitope) within 2D membranes is controlled aiming at mastering the adhesion of human dermal fibroblasts under serum-free culture conditions. The membranes were characterized with respect to their microstructure, by scanning electron microscopy (SEM), epitope distribution, degradability and cell behavior, regarding adhesion, proliferation and cytoskeleton organization. SEM of the membrane surface showed a network of nanofibers that are remarkably reminiscent of the filamentous structure found in the ECM. Confocal microscopy images, using a fluorescently labeled RGDS-peptide, showed that the RGDS signal is uniformly distributed on the membranes. Degradation studies indicated that the membranes are susceptible to enzymatic degradation by hyaluronidase. In the presence of the enzyme at physiological concentration, the membranes degrade gradually over time. When grown on membranes with the cell recognition epitope RGDS, fibroblasts had spread out and elongated, exhibiting extended filopodia interacting with fibrillar structure of the membrane surface, thus showing improved adhesion to the substrate. This study demonstrates the positive effect of the RGDS epitope, presented on a self-assembled membrane, in promoting cell-matrix interactions.