Purpose: There is a growing interest in fabrication of bioinks which on one hand biocompatible and on the other hand possess mechanical properties which would allow to fabricate stable constructs capable to survive for a long time after transplantation. Although choosing appropriate material is essential for bioprinting, there is however, another, equally important issue extensively studied nowadays - inclusion of vasculature system within fabricated scaffolds.

Methods: In the following study we designed artificial channel bioprinted of ECM based so called “bioink A” to investigate if essential for neovascularization endothelial cells (HUVEC) and fibroblasts (aHDF) with proportions of 1:2 (8 mln/mL in total), would adhere to the material. Additionally, a media flow through such perfused channel was set to stimulate cell adhesion and proliferation. Fiber of bioink A which formed vault of a channel was printed either parallelly or perpendicularly to the direction of media flow. Two ways of seeding cells was tested. Channel was either printed with cell-laden so called “bioink B” or cells were delivered to the channel directly, with pipetting. In each seeding variant, a total of 4·105 cells per channel were used. After 2, 5, 8 or 24h of incubation, media flow was applied. After 8 days of experimental trial for each time variant, the channels were stored in formaldehyde and immunohistochemical staining was made to investigate the presence of cells on channel walls and vault.

Results: Cells adhered for both ways of fiber arrangement, however parallel bioprint with 5h of incubation and direct cell seeding resulted in better adhesion efficiency. After 5h of incubation, before flow was set, 2.1·105 cells stayed in channel with 75% viability. The quantity of cells did not decreased over time, until the end of experiment. Hematoxylin & Eosin staining showed that after 8 days cells were uniformly distributed across vault of a channel.

Conclusions: Our study clearly shows that cells which promote neovascularization adhere efficiently to pancreatic, ECM based bioink. It proves that bioink A of pancreatic origin can be used also for other than pancreatic cells type. Presented in this research bioink B can be used for other studies as vector for cell seeding.