Cell-Seeding Promotion of Phages Functionalized Surfaces

Regenerative medicine is a developing field of interdisciplinary research that includes a combination of <i>in vitro/ex vivo</i> and <i>in vivo</i> techniques, including the transplantation of stem/progenitor, differentiated, or modified cells, either alone or in biomaterial scaffolds. Many strategies have been developed based on the stimulation of body’s endogenous process to grow and repair.<br/>Phage display represent a powerful, high-throughput method for discovering peptide ligands for a specific target. The method uses a library of phage particles containing a wide range of peptides or proteins to identify those that bind to a specific target. This technique has evolved and now it contributes to a variety of different areas of medicine and technology, i.e., targeted drugs, imaging diagnosis, gene delivery and nanomaterials. It is a low-cost technique for screening peptide ligands on cells or tissues, distinguishing between small changes in cell surface phenotypes and between normal and sick tissues. In particular, phage-derived peptides can be used to functionalize synthetic scaffolds to drive stem cell proliferation and differentiation in vitro.<br/>In this communication we will show how self-organization processes of phages on model substrates, at the liquid/solid interface, promotes anisotropic nanometric alignments of these macromolecular systems, characterized by peculiar nanosized diameters, with lengths of the order of micrometre. The further goal, however, is to correlate the capability of organized phage assemblies to efficiently promote specific processes of "cell seeding" and, in turn, developing suitable control strategies of the phage organization, based on the tuning of pH and surface free energy, as a preliminary step in the development of efficient scaffold functionalization strategies for tissue regeneration. The efficiency of the adopted surface functionalization technique was evaluated by using AFM, while the cell-response has been assessed by optical microscopy and by Force Spectroscopy, focusing the attention on the effect of phages on the mechanical properties of the extracellular matrix. We think that these studies may pave the way to a tailored use of surfaces functionalized with phages, as a smart scaffold able to increase the beneficial cell response.