Cell viability characterization of bioprintable blood-vessel-like cellular channels towards 3D organ fabrication

Organ printing, or layer-by-layer additive tissue fabrication, is a revolutionary concept that has recently emerged as an interdisciplinary effort to produce three-dimensional living organs for clinical applications. However, it is a complex and challenging process to execute due to the lack of fundamental understanding of tissue and organ formation. One of the major challenges is inclusion of blood-vessel-like channels between layers to support cell viability in terms of nutrients and oxygen transport. In this research, we developed novel printable micro-fluidic channels encapsulating cells to mimic natural blood vessels. Our previous research addressed the printability of novel vessel-like micro-fluidic channels with alginate hydrogel with co-axial nozzle assembly. In this study, we further investigated the influence of bioprinting parameters on the viability of cartilage progenitor cells (CPCs) during and after printing. The results of this study revealed that quantifiable cell death could be induced by varying dispensing pressure, co-axial nozzle geometry, and biomaterial concentration. However, damaged cells were able to recover during incubation, as well as to undergo proliferation to a certain extent. These findings may serve as a guideline for optimizing our system as well as predicting cell damage in future studies.