Micro- and Macrobioprinting: Current Trends in Tissue Modeling and Organ Fabrication.

The recapitulation of human anatomy and physiology is critical for organ regeneration. Due to this fundamental requirement, bioprinting holds great promise in tissue engineering and regenerative medicine due to the possibility of fabricating complex scaffolds that host cells and biochemical cues in a physiologically relevant fashion. The ever-growing research in this field has been proceeding along two different, yet complementary, routes: on the one hand, the development of bioprinting to fabricate large tissue surrogates for transplantation purposes in vivo (macrobioprinting), and on the other the spread of bioprinting-based miniaturized systems to model the tissue microenvironment in vitro (microbioprinting). The latest advances in both macro- and microbioprinting are reviewed, emphasizing their impact on specific areas of tissue engineering. Additionally, a critical comparison of macro- versus microbioprinting is presented together with advantages and limitations of each approach. Ultimately, findings obtained both at the macro-and microscale are expected to provide a deeper insight in tissue biology and offer clinically relevant solutions for organ regeneration.