Biofabrication of 3D cell-encapsulated tubular constructs using dynamic optical projection stereolithography.

It has been widely recognized that one of the critical limitations in biofabrication of functional tissues/organs is lack of vascular networks which provide tissues and organs with oxygen and nutrients. Biofabrication of 3D vascular-like constructs is a reasonable first step towards successful printing of functional tissues and organs. In this paper, a dynamic optical projection stereolithography system has been implemented to successfully fabricate 3D Y-shaped tubular constructs with living cells encapsulated. The effects of operating conditions on the cure depth of a single layer have been investigated, such as UV intensity, exposure time, and cell density. A phase diagram has been constructed to identify optimal operating conditions. Cell viability immediately after printing has been measured to be around 75%. Post-printing mechanical properties, swelling properties, and microstructures of the gelatin methacrylate hydrogels have been characterized. The resulting fabrication knowledge helps to effectively and efficiently print tissue-engineered vascular networks with complex geometries.