Hydrogels Essay -- Ethics, Bioprinting, Artificial Tissues

Tissue or organ printing approaches became popular due to lack of organ donors. To address this need, cells or biological molecules are embedded within hydrogels and these mixtures are printed with computer controlled rapid prototyping systems to yield printed organs (9). Bioprinting approaches are promising high-throughput techniques to create artificial tissues and organs for tissue engineering. Gels with or without cells/biological factors are printed on predefined positions layer by layer fashion (Figure 1) with the final goal of fixing damaged or diseases tissues (8, 9). Using this technique, cells can be homogeneously distributed within a hydrogel matrix on predefined positions. This technique is a potential remedy for the cases where cell seeding results in random cell distribution on solid scaffolds. Nozzle diameter, cell density, liquid rheology and operation temperature are the main factors, which affect printing quality in bioprinting based techniques (11, 33, 34). Patterning of cell or biological molecule loaded hydrogels have been widely performed by computer controll...