3D bioprinting: a review of materials, processes and bioink properties

Abstract

3D bioprinting is an addictive manufacture method for 3D scaffold engineering used as a 3D template for cell attachment, growth and subsequent tissue formation. In this method, the “inks” used for printing are made from biomaterials that can be formulated and printed with cells added before or after the process. One of the most used biomaterials for bioinks is hydrogel due to its high water composition, biocompatibility and tailorable properties that facilitate the 3D bioprinting process and provide favorable extracellular environment for cell functions. The 3D bioprinting techniques are divided into extrusion, inkjet and laser-assisted printing, each requiring specific rheologic properties for a satisfactory printing process. One of the biggest challenges in 3D bioprinting is its optimization, which depends on 3D structural complexity, materials’ properties and bioink development for the “bioprinting window”. This work aims to review the state of the art of hydrogels’ most common classifications and materials, the physics of each bioprinting technique and the properties affecting printability and cell viability.