A new generation of transcatheter heart valves
region of interest. Cell-seeded biological sutures, formed from fibrin microthreads, overcome these issues and have demonstrated increased cell engraftment. To increase the number of cells that can be seeded on these biological sutures, we investigated coating them with ECM proteins. Methods: Biological sutures were produced by bundling twelve fibrin microthreads. Surface modified sutures were created by coating with poly-l-lysine or vitronectin. Sutures were then seeded with 100,000 human mesenchymal stem cells for 24 h. Seeded sutures were spun in an in vitro shear stress model to assess cell adhesion. To evaluate the ability of cells to align along the length of the suture, nuclear alignment was determined. Results: Vitronectin coating significantly increased the number of cells seeded on fibrin sutures (19604±1829 cells/cm) compared to unmodified sutures (6821±739 cells/cm; Pb.05) and sutures modified with poly-l-lysine (4226±1003 cells/cm; Pb.05). Spinning resulted in similar decreases in cell number in all groups. Unmodified sutures had more aligned nuclei between suture surfaces (Pb.05 vs. poly-l-lysine and vitronectin). All suture types had increased alignment compared to cells grown on plates (Pb.001). Conclusions: Vitronectin coating increases the number of cells seeded on fibrin microthread based biological sutures. Cell adhesion strength was not altered with vitronectin coating, suggesting that delivery of stem cells to the heart may be similar to the 65% delivery efficiency seen with uncoated fibrin microthread sutures.