Pegylation of fibronectin and its functional domains: Effect on stability and biological activity

Delayed wound healing in many chronic wounds has been linked to the lack of extracellular matrix (ECM) support and the degradation of fibronectin (FN) by an abnormally high protease level. The ECM provides physical and chemical cues that direct tissue growth and development while FN is a key ECM protein that attracts and binds different molecules and cells. The goal of my study is creating an ECM analogue based on a composite of polyethylene glycol (PEG) hydrogels and FN binding domains and stabilizing FN against proteolytic degradation by conjugating it to PEG.;The work presented here shows a two-prong approach by which the problem of ECM degradation and deficiency chronic wound healing can be addressed. The first approach for addressing ECM deficiency is through a scaffold design methodology. The novelty of the scaffold approach is that it uses the cell-binding domains of FN instead of the often-used RGD peptide. I demonstrate that a PEG hydrogel with the cell-binding domain produces a more robust biological response in cells than a PEG hydrogel with the RGD peptide. I also demonstrate that varying different functional domains of FN can be used to controllably stimulate multiple biological responses. The second approach demonstrates a method by which FN, a key ECM protein, is stabilized against proteolytic degradation without perturbing its activity. These studies of creating PEG-FN conjugates are the first of their kind. Collectively, the data that I present in this thesis will lead to novel therapeutic methods for treating chronic wounds.