Abstract
Recently, researchers have challenged to create three-dimensional (3-D) tissues in order to establish in vitro models and new therapy for damaged organ. We have developed cell-sheet and successfully fabricated pulsatile 3-D myocardial tissues by stacking myocardial cell sheets. However, in vitro scaling up of 3-D tissues is limited due to lack of vessels supplying oxygen and nutrition, removing waste molecules. In this study, we have developed novel bioreactor culturing cell sheets on collagen-based microchannels and examined cell behavior between tissues and channels. Rat cardiac cells including endothelial cells cultured on a temperature responsible culture dish for 4 days. By lowering temperature, confluent cardiac cells were harvested as an intact cell sheet. Collagen-based microchannels were engineered by gelling collagen around parallel stainless wires and extracting the wires. The multi-layered cell sheet was put on the collagen-gel base with microchannels and the device was connected to the novel bioreactor system. After 5 days of cultivation, rat blood was perfused into the microchannels for checking the flow and the tissue sections were stained with Hematoxylin-Eosin. HE staining demonstrated that layered cell sheets tightly connected onto the collagen microchannels. The cells migrated into collagen gel and formed like capillaries. Some cells reached to the microchannels and covered over inner surface. The perfused blood cells flew the capillaries between cell sheets and the collagen-based microchannels. We have successfully fabricated 3-D tissues with perfused vascularized capillaries. These results showed new insights regarding in vitro vascular formation and indicated the possibility of fabricating vascularized 3-D tissues.
