Bioactive Ions-Loaded Bioinks Primed for 3D Printing of Artificial Tissues

Bioactive ions have become increasingly important in tissue engineering due to their ability to improve cellular activity by modifying both cell–material and cell–cell interactions. Inorganic biomaterials have additional attributes such as mechanical properties and drug delivery. Recently, many studies have focused on fabricating three-dimensional (3D) scaffolds utilizing inorganic ions, such as bioceramics and bioactive glass, using 3D bioprinting technology. 3D bioprinting has emerged as a focal point for innovative tissue and organ reconstruction approaches. The aim of this review is to summarize the mechanisms by which inorganic ions affect the regeneration of tissues and to summarize research on 3D-printed scaffolds utilizing bioactive ions. The review summarizes how recently used inorganic ions induce biological responses in tissue regeneration through signal transduction pathways. Studies on 3D-printed scaffolds using newly developed inorganic ion-releasing hydrogels were summarized, focusing on functions that improved cell proliferation and differentiation ability or increased effectiveness in in-vivo experiments. Finally, the review discusses the difficulties and prospects for scaffolds using these inorganic ion-releasing bioinks.