An Integrated Micro-nano-fibrous Bilayered Small-Diameter Vascular Graft Simultaneously Supporting Endothelial and Smooth Muscle Cells

A good vascular graft should have a biomimetic integrated layered structure and simultaneously facilitate the formation of endothelial cell monolayer and proliferation of vascular smooth muscle cells (SMCs). Herein, we report an integrated bilayered small-diameter vascular graft consisting of a dense inner layer of bacterial cellulose (BC) nanofibers and saponified cellulose acetate (SCA) microfibers and a macroporous outer layer of BC. The integrated bilayered graft is fabricated by a combined method of electrospinning, in situ biosynthesis, and laser ablation. Scanning electron microscopy (SEM) analysis confirms that the BC nanofibers run through the inner and outer layers, leading to an integrated bilayered graft, and average pore size in the outer layer is 225.4 μm. In case of the integrated structure, the bilayered graft shows the suture retention of 0.68 N and 0.54 N in the dried and wet states, respectively. In vitro hemocompatibility experiments show that the BC/SCA inner layer exhibits good hemocompatibility. Furthermore, the compact micro-nano-fibrous inner layer favors endothelialization, while the macroporous outer layer promotes growth and proliferation of SMCs, thus achieving control over specific cellular behavior in respective layers. The unique integrated bilayered vascular graft exhibits the required mechanics, good hemocompatibility and biocompatibility and thus holds great promise for use as a blood vessel substitute.