Vascularized cardiac tissue construction with orientation by layer-by-layer method and 3D printer.

Herein, we report the fabrication of native organ-like three-dimensional (3D) cardiac tissue with an oriented structure and vascular network using a layer-by-layer (LbL), cell accumulation and 3D printing technique for regenerative medicine and pharmaceutical applications. We firstly evaluated the 3D shaping ability of hydroxybutyl chitosan (HBC), a thermoresponsive polymer, by using a robotic dispensing 3D printer. Next, we tried to fabricate orientation-controlled 3D cardiac tissue using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) and normal human cardiac fibroblasts (NHCF) coated with extracellular matrix (ECM) nanofilms by layer-by-layer technique. These cells were seeded in the fabricated rectangular shape HBC gel frame. After cultivation of the fabricated tissue, fluorescence staining of the cytoskeleton revealed that hiPSC-CM and NHCF were aligned in one direction. Moreover, we were able to measure its contractile behavior using a video image analysis system. These results indicate that orientation-controlled cardiac tissue has more remarkable contractile function than uncontrolled cardiac tissue. Finally, co-culture with human cardiac microvascular endothelial cells (HMVEC) successfully provided a vascular network in orientation-controlled 3D cardiac tissue. The constructed 3D cardiac tissue with an oriented structure and vascular network would be a useful tool for regenerative medicine and pharmaceutical applications.