Cell seeding strategies for silk fibroin meshes

Abstract

The aim of this study is to introduce a silk fibroin mesh coated with autologous tissue, for use in a one-step surgical procedure for soft tissue repair. The coating with SVF (stromal vascular fraction) is of particular importance because the heterogeneous mesodermal cell population combined with silk mesh might greatly improve hernia healing. To establish a suitable mesh, biomaterial silk was knitted to a mesh and degummed. This silk fibroin mesh was placed over CellcrownTM for the in vitro experiments. The silk fibroin was grafted with lectin WGA (wheat germ agglutinin), which increased its binding affinity for cells. The generated meshes were then tested using a cytotoxicity assay and incorporated different seeding strategies, using different variations of the adhesion time. The aim was to find a suitable coating of the silk meshes with the maximum possible cell adhesion. First, two silk fibroin fibres were compared to identify the best silk source in terms of biocompatibility. Lymphocyte cell activation was measured in vitro as an immunologic response to the silk fibroin meshes. On the basis of the generated laboratory data, a silk fibroin fibre was selected. Second, different seeding strategies were applied using different adhesion times. The silk fibroin fibres were coated with fibroblasts NIH3T3 and hASC (human adipose-derived mesenchymal stem cells). These cells adhered better to the silk fibroin grafted with lectin WGA. We also found that SVF coating to the silk fibroin meshes did not improve with lectin WGA coating. When the suspension of SVF was dripped onto the silk fibroin mesh, the SVF adhered in clusters, suggesting that the silk mesh acted as a filter to hold back the SVF. The SVF thus formed a layer that surrounded the silk fibroin and covered the silk mesh with autologous cells.