Natural/Synthetic Polymer Materials for Bioink Development

Three-dimensional (3D) printing (or additive manufacturing) is a manufacturing technology that produces 3D objects layer-by-layer automatically. Since the 1980s, 3D printing has been used in various fields, ranging from automobiles to medicine. In regenerative medicine and tissue engineering fields, this technique has developed with the advance of the ink material mostly composed of the live cells within. Additionally, it is also required to meet the mechanical durabilities, easy printability, and low toxic effects or immunogenicity. Therefore, it is essential to consider the suitability of ink materials in 3D bio-printing. Various printing materials can be selected, whether single or hybrid, by incorporating two or more inks. Among them, this paper focuses mainly on two major categories: natural polymers and synthetic polymers. The natural polymers have similar properties with extracellular matrix, biocompatibility, and biodegradability. On the other hand, synthetic polymers have adjustable mechanical properties and crosslinking ability according to various stimuli. This paper describes the properties, advantages/disadvantages, and applications of bioink material candidates.