(15f) Collagen Gel Effects On Smooth Muscle Cell Seeding Efficiency and Function in Chitosan Scaffolds

Successful engineering of large diameter vascular grafts requires an effective seeding method that aids smooth muscle cell organization as well as retention of synthesized collagen and elastin. The aim of this study was to improve the seeding efficiency and long term performance of vascular smooth muscle cells (SMCs) in our chitosan-based vascular graft using a biological relevant matrix such as collagen gel. We fabricated highly porous, tubular scaffolds made from a 1.5 wt%, 9:1 chitosan: collagen solution, using a freeze drying method. The chitosan-collagen scaffold was then covalently derivatized with carboxymethylated dextran sulfate. The scaffolds were equilibrated in culture medium then dehydrated prior to seeding. Then, they were seeded with porcine aortic SMC suspended in various dilutions of a collagen gel solution (1.1 mg collagen/ml, pH 7.4). The cell-collagen suspension was allowed to gel prior to immersion in culture medium. Histology and viability assays after 10 days of static culture demonstrated improved cell survival and growth when seeded with collagen gel.The trophic effects were present even with substantially diluted collagen gels. Lower gel concentrations also produced significant improvements in cell distribution. Perfusion cultures are ongoing and quantitative results of matrix protein synthesis and scaffold mechanics will be reported.