A Novel Fibrous Collagen Scaffold for Patterning Vascular Development and Regenerating the Myocardium

Promoting angiogenesis in engineered cardiac tissue is a significant challenge that limits our ability to remuscularize injured myocardium. Biochemical cues from growth factors and cytokines sequestered in the extracellular matrix (ECM) stimulate wound healing and angiogenesis but the distribution of these signaling molecules in biomaterials does not yield spatial control over vessel formation. We aim to develop a heparin-conjugated, patterned, collagen microfiber scaffold to sequester and prolong the release of growth factors in vivo and direct vascular development in engineered human cardiac tissue. Ongoing work uses 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) chemistry to covalently link heparin (Hep-COOH) to type I collagen in solution. EDC and N-hydroxysuccinimide (NHS) were added to a 2% (w/v) solution of heparin in 0.05M MES buffer (pH 5.60) at a molar ratio of EDC : NHS : Hep-COOH of 0.4 : 0.24 : 1.0. Collagen I (13mg/mL) was equilibrated then added to the EDC/NHS activated heparin solution. Fourier-transform infrared spectroscopy (FTIR) revealed S=O asymmetric stretching at 1230cm^-1 and S-O-C stretching at 990cm^-1 and ~800cm^-1 on heparin-modified collagen, suggesting that heparin was conjugated to collagen via carbodiimide chemistry. Heparin-modified collagen will be used to synthesize wet-spun collagen microfiber scaffolds and bind growth factors, providing both spatial and temporal control over the position and release kinetics of growth factors in vivo. Scaffolds will then be embedded in bulk collagen hydrogel with human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes to create a composite material conducive to tissue remodeling and cell infiltration. We expect these patterned microfiber scaffolds to direct host endothelial cell migration and vascular development in a rat ischemia/reperfusion (I/R) model. This approach will allow us to harness native capabilities of host vascularization to increase vessel penetration and architecture of implants in vivo.