Stable and Active bFGF-Polymer Conjugates for Wound Healing

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DESCRIPTION (provided by applicant): Acute and chronic wounds cause pain and suffering, in addition to significant morbidity and risk of infection, to a large number of people each year. As a result, there is considerable need for new therapeutics that induces and accelerate wound repair. Basic fibroblast growth factor (bFGF) stimulates the proliferation and migration of several cell types that have crucial roles in wound healing. However, the protein is rapidly degraded when delivered or upon storage, thus far preventing its therapeutic use. One objective of this research is to stabilize bFGF by covalently conjugating a synthetic polymer that mimics a natural protector of the protein, heparin. bFGF induces dimerization of its receptors and heparin aids in receptor activation. Thus, a second objective on this research is to produce dimeric polymer conjugates of bFGF in order to increase the mitogenic and migratory cellular activity of the protein relative to unmodified bFGF. The third objective is to test preclinical efficacy of the bFGF conjugates to heal wounds. Three specific aims are proposed to reach these objectives. The first aim is to evaluate the stability of bFGF-p (SS)-co-PEGMA polymer conjugates compared to controls and cytotoxicity of the polymers. It is hypothesized that bFGF- p (SS)-co-PEGMA will be more stable than bFGF-pPEGMA, bFGF-PEG and the unmodified protein, and the polymers will be nontoxic at therapeutically useful concentrations. To accomplish this, stability of the bFGF conjugate against trypsin, acidic pH, heat, stirring, and storage will be quantified by standard biochemical and cellular assays. The second aim is to determine in vitro bioactivity of bFGF-p (SS)-co-PEGMA-bFGF conjugates. It is hypothesized that dimeric bFGF p (SS)-co-PEGMA conjugates will be more active in human dermal fibroblast (HDF) and human dermal keratinocyte (HDK) cell proliferation and migration assays than the monomeric conjugates and bFGF alone. To investigate this, conjugate-induced stimulation of cell proliferation and migration of cells in vitro will be ascertained. Receptor activation will be verified. The third aim is to determine the ability of dimeric and monomeric bFGF sulfonated polymer conjugates to enhance wound healing. It is hypothesized that dimeric bFGF p(SS)-co-PEGMA conjugates will be more effective at healing normal and diabetic wounds in vitro and in vivo than the monomeric conjugate or bFGF alone. To test this, organotypic cultures and superficial wounding models in mice will be employed. One potential outcome of this research is to develop an active agent that promotes skin repair. The long-term goal of this research is to produce efficacious and stable therapeutics to treat acute and chronic wounds.