3D extrusion bioprinting: rational bioink design and advanced fabrication techniques

The field of 3D extrusion bioprinting has rapidly evolved, presenting significant advancements in tissue engineering applications. Traditionally, the development of printable hydrogel formulations has relied more on empirical approaches rather than rational design principles. However, to better mimic the dynamic and spatiotemporal nature of the extracellular matrix (ECM), novel bioinks with tunable properties and synthetic flexibility are being developed. Simultaneously, variations of extrusion bioprinting methods have been developed to improve the fabrication of sophisticated tissue patterns to emulate their in vivo counterparts. This review will provide a focused overview of recent advancements in bioink design and extrusion bioprinting technologies. By addressing the latest developments in these strategies, this review aims to offer insights into the future direction of extrusion bioprinting.