A Review on 3D Bioprinting Techniques and Bioinks

With the exciting advancement in medical knowledge, the production or replacement of tissue or organs has the gold standard in the treatment of some diseases and lesions. Bioprinting technology is a breakthrough in this field. In line with the evolution of this technology, the development of advanced printers and new biomaterials are the factors affecting achievement of recent advances, which is partially due to the reproducibility and scaffold regeneration with the intended architecture. In this paper, the basic definitions of the three- dimensional (3D) bioprinting technology and the main elements associated with this technology are reviewed. This review aims are to focus on different technologies developed for the printing of biological species. A brief description of complicated nozzle geometry is followed by introducing common bioinks and the requirements for ideal biomaterials, especially hydrogels as novel candidates and their preparation aspects. Architectural, mechanical and biological properties of a scaffold are the most essential characteristics of a printed structure which are affected by the internal structure and the hydrogel precursor. Since innovation in biomaterials is key to the success of bioprinting, hydrogel preparation methods are fully discussed in terms of network formation. By incorporating proper instrumental parameters and tailoring hydrogel precursors, many benefits can be imparted to the final scaffold, providing design elements for next-generation bioinks.