Characterization of vessel-like printable cellular microfluidic channel

Organ printing is a complex and challenging process to execute due to the lack of fundamental understanding of tissue and organ formation. Many challenges impede the further development of artificial organs for tissue engineering. These challenges include high cell seeding density, integration of blood vessels for cell viability, seeding spatially organized multiple cell types, and the degradation process and associated by-products. Use of an embedded micro-fluidic network during organ printing provides a way to overcome the above mentioned problems. In this research, a new approach is presented in tissue engineering through the development of novel printable vessel-like permeable micro-fluidic channels in support of organ printing. The proposed micro-fluidic channels in this work enable media transport through diffusion and support the mechanical integrity of the extracellular matrix in 3D. The proposed technique can be easily integrated with an additive stem cell printing process in tandem, significantly enabling cell viability in 3D. In this research, a pressure-assisted solid freeform fabrication platform is developed with a coaxial needle dispenser unit to print hollow hydrogel filaments. Hydrogel flow rheology through a coaxial nozzle system is studied. The effects of biomaterial concentration, crosslinker concentration, and biomaterial types are explored to understand the bioprintability of micro-fluidic channels. In addition, cell viability is presented in this paper and shows that cells maintained their viability both right after bioprinting and during prolonged in vitro culture.