A comprehensive review on hydrogel-based bio-ink development for tissue engineering scaffolds using 3D printing

Abstract

Three-dimensional (3D) bioprinting technology allows the production of porous structures with complex and varied geometries, which facilitates the development of equally dispersed cells and the orderly release of signal components. This is in contrast to the traditional methods used to produce tissue scaffolding. To date, 3D bioprinting has employed a range of cell-laden materials, including organic and synthetic polymers, to construct scaffolding systems and manufacture extracellular matrix (ECM). Still, there are several challenges in meeting the technical issues in bio-ink formulations, such as the printability of bio-inks, the customization of mechanical and biological properties in bio-implants, the guidance of cell activities in biomaterials, etc. The main objective of this article is to discuss the various strategies for preparing bio-inks to mimic native tissue's extracellular matrix environment. A discussion has also been conducted about the process parameters of bio-ink formulations and printing, structure requirements, and fabrication methods of durable bio-scaffolds. The present study also reviews various 3D-printing techniques. Conclusively, the challenges and potential paths for smart bioink/scaffolds have been outlined for tissue regeneration.