Bioinks and bioprinting: A focused review

Abstract Bioprinting is a process based on additive manufacturing that uses biomaterials as the microenvironment for living cells. These materials often referred to as bioinks, are based on cytocompatible hydrogel precursors, which gel in a manner compatible with different bioprinting approaches. Hydrogels are highly hydrated three-dimensional (3D) networks of cross-linked hydrophilic polymer chains and have been widely explored for use as bioactive delivery agents, cell carriers, consumer products, tissue engineering scaffolds and for wound healing. Hydrogels can be tailored for different chemical, electrical, mechanical, and thermal properties and can even be made to conduct electricity. Recent trends in bioink development have focused on incorporating carbon-based nanomaterials, clay nanomaterials, ceramics, fibers, and growth factors to create hybrid and multi-composite hydrogels. The goal of this review paper is to examine the synergies resulting from the combination of these materials. This review will feature recent advances in this field, focusing on bioink developments and bioprinting applications, and the use of natural and synthetic additives that impart unique, novel, or critical functionalities.