Fabrication of 3D Tissue-Like Structure Ussing Magnetite Nanoparticles and Magnetic Force

Novel technologies to establish 3D tissue-like constructs are desired for tissue engineering. In the present study, magnetic force and magnetite nanoparticles were used to construct a layered mesenchymal stem cell (MSC) sheet, a layered cardiomyocyte sheet, and a layered fibroblast sheet involving capillaries. Magnetite cationic liposomes (MCLs) were taken up by the target cells. When a magnet was set under a tissue culture dish, magnetically labeled target cells were attracted and then adhered to form a layered cell sheet. MSC sheets were harvested and transplanted into the bone defect in cranium of nude rats, resulted in formation of new bones surrounded by osteoblast-like cells. For cardiomyocyte sheets, the immunofluorescence staining revealed the existence of gap junctions within the cardiomyocyte sheets. For fibroblast sheets, normal human dermal fibroblasts (NHDFs) sheets contained the major dermal extracellular matrix components. Human umbilical vein endothelial cells (HUVECs) were co-cultured with NHDF sheets, resulted in tube-like formation of HUVECs. These results suggest that this novel use of magnetite nanoparticles and magnetic force, which we refer to as "magnetic force-based tissue engineering (Mag-TE)", offers a major advancement in tissue engineering