Page - (000247) - in Biomedical Chemistry: Current Trends and Developments

Polymers to Mimic Natural ECM New generations of synthetic biomaterials are being developed not only to provide structural support for damaged tissues, but also to integrate with these tissues and ideally promote regeneration. The surface of biomaterials can be functionalized with specific factors that are capable of modulating cell behaviour to promote wound healing and tissue regeneration (Bellis, 2011). Synthetic ECMs replace many functions of the native ECM: organizing cells into a three-dimensional architecture, providing mechanical integrity to the new tissue and providing a hydrated space for the diffusion of nutrients and metabolites to and from the cell (Rowley, 1999). Cell adhesion is not only critical for stimulating proper tissue development at implant/tissue interfaces, but also necessary for materials that serve as carriers for the delivery of reparative cells to wound sites. Furthermore, cell attachment to a biomaterial scaffold is an important early step in the generation of in vitro-engineered tissue substitutes. There are several molecular interactions that can mediate cell attachment, however much of the research in this area has focussed on utilizing pro-adhesive factors, such as adhesive peptides, that engage and activate integrin adhesion receptors on the cell surface. Integrins are heterodimeric transmembrane receptors that bind to proteins within the ECM including fibronectin, laminin, various collagens, and many other molecules (Bellis, 2011). The most widely studied cell-adhesive peptide in the biomaterials field is the oligopeptide Arg-Gly-Asp (RGD), identified as the minimal essential cell-adhesion sequence in fibronectin (Ruoslahti & Pierschbacher, 1987; Cha, 2012). The incorporation of this motif as described initially by Rowley is highly effective at promoting the attachment of numerous cell types to a plethora of diverse materials (Rowley, 1999; Bellis 2011). The RGD sequence can bind to multiple integrin species, and synthetic RGD peptides offer several advantages for biomaterials applications. Because integrin receptors recognize RGD as a primary sequence (although conformation of the peptide can modulate affinity), the functionality of RGD is usually maintained throughout the processing