Bioink design for extrusion-based bioprinting

Abstract Extrusion-based bioprinting (EBB) is the most important printing method for 3D bioprinting creating substitute organs because of its affordability and maneuverability. In bioinks for extrusion bioprinting, cells and materials are stacked layer by layer in a spatially controlled pattern to create living tissues and organs. Bioink in the 3D bioprinting process acts as a carrier of the laden cells for printing, is a mixture of cells, biomaterials, and biological active substances, determines the survival rate of the cells to print, cell growth after printing, the precision of the printed organs, the methods to print. According to the cognitive process and design route of bioinks used for extrusion-based bioprinting, the present review introduced (i) concept, development, and basic composition of bioink, (ii) the basis of bioink-materials selection for extrusion printing—general properties, (iii) referential strategies to design bioinks, which implement the extrusion printing process and (iv) new strategies to develop novel bioinks. At last, the paper summarizes the current challenges and the future development trend of bioinks.