Bioprinting small-diameter vascular vessel with endothelium and smooth
muscle by the approach of two-step crosslinking process
Three-dimensional (3D) bioprinting shows great potential for autologous
vascular grafts due to its simplicity, accuracy, and flexibility. 6mm
diameter vascular grafts are used in clinic. However, producing
small-diameter vascular grafts are still an enormous challenge.
Normally, sacrificial hydrogels are used as temporary lumen support to
mold tubular structure which will affect the structure’s stability. In
this study, we develop a new bioprinting approach to fabricating
small-diameter vessel using two-step crosslinking process. ¼ lumen wall
of bioprinted gelatin mechacrylate (GelMA) flat structure is exposed to
ultraviolet (UV) light briefly for having certain strength, while ¾
lumen wall shows as concave structure remained uncrosslinked.
Pre-crosslinked flat structure is merged towards the uncrosslinked
concave structure. Two individual structures will be combined tightly
into an intact tubular structure by receiving more UV exposure time.
Complicated tubular structures are constructed by these method. Notably,
the GelMA-based bioink loaded with smooth muscle cells (SMCs) are
bioprinted as the outer layer and human umbilical vein endothelial cells
(HUVECs) are seeded onto the inner surface. A bionic vascular vessel
with dual layers is fabricated successfully and keeps good viability,
and functionality. This study may provide a novel idea for fabricating
biomimetic vascular network or other more complicated organs.