Three-dimensional (3D) bioprinting is an evolving technique that is expected to revolutionize the field of regenerative medicine. Since the organ donation does not meet the demands for transplantable organs, it is important to think of another solution, which may and most likely will be provided by the technology of 3D bioprinting. However, even smaller parts of the printed renal tissue may be of help, e.g. in developing better drugs. Some simple tissues such as cartilage have been printed with success, but a lot of work is still required to successfully 3D bioprint complex organs such as the kidneys. However, few obstacles still persist such as the vascularization and the size of the printed organ. Nevertheless, many pieces of the puzzle are already available and it is just a matter of time to connect them together and 3D bioprint the kidneys. The 3D bioprinting technology provides the precision and fast speed required for generating organs. In this review, we describe the recent developments in the field of developmental biology concerning the kidneys; characterize the bioinks available for printing and suitable for kidney printing; present the existing printers and possible printing strategies. Moreover, we identify the most difficult challenges in printing of the kidneys and propose a solution, which may lead to successful bioprinting of the kidney.
