Scaffold-Free Bio-3D Printing Using Spheroids as "Bio-Inks" for Tissue (Re-)Construction and Drug Response Tests

In recent years, scaffold-free bio-3D printing using cell aggregates (spheroids) as "bio-inks" has attracted increasing attention as a method for 3D cell construction. Bio-3D printing uses a technique called the Kenzan method, wherein spheroids are placed one-by-one in a microneedle array (the "Kenzan") using a bio-3D printer. The bio-3D printer is a machine that was developed to perform bio-3D printing automatically. Recently, it has been reported that cell constructs can be produced by a bio-3D printer using spheroids composed of many types of cells and that this can contribute to tissue (re-)construction. This progress report summarizes the production and effectiveness of various cell constructs prepared using bio-3D printers. It also considers the future issues and prospects of various cell constructs obtained by using this method for further development of scaffold-free 3D cell constructions.