Effective seeding of smooth muscle cells into tubular poly(trimethylene carbonate) scaffolds for vascular tissue engineering

Porous tubular poly(trimethylene carbonate) (PTMC) scaffolds for vascular tissue engineering, with an inner diameter of 3 mm and a wall thickness of 1 mm, were prepared by means of dip-coating and subsequent leaching of NaCl particles. The scaffolds, with an average pore size of 110 μm and a porosity of 85%, showed a smooth muscle cell (SMC) seeding efficiency of only 10%. To increase the efficiency of cell seeding, these scaffolds were coated with a microporous PTMC outer layer with a thickness of 0.1–0.4 mm, an average pore size of 28 μm, and a porosity of 65%. Coating of the scaffolds with the microporous outer layer did not influence the inner pore structure or the mechanical properties of the scaffolds to a significant extent. The intrinsic permeability of the scaffolds decreased from 60 × 10−10 m2 to approximately 5 × 10−10 m2 after coating with the microporous outer layer. The latter value is still relatively high indicating that these scaffolds may facilitate sufficient diffusion of nutrients and waste products during cell culturing. The efficiency of SMC seeding determined after 24 h cell adhesion in the scaffolds increased from less than 10% to 43% after coating with the microporous outer layer. The cells were homogeneously distributed in the scaffolds and cell numbers increased 60% during culturing for 7 days under stationary conditions. It is concluded that coating of porous tubular PTMC scaffolds with a microporous PTMC outer layer facilitates effective cell seeding in these scaffolds.