Review of extrusion-based multi-material bioprinting processes

Abstract

Scaffold-based tissue engineering aims to provide patients with permanent solutions to damaged organs and tissues based on engineered scaffolds. For this, extrusion-based bioprinting has drawn considerable attention for scaffold fabrication due to its ability to print a variety of biomaterials or their mixtures with living cells, as well as its simple construction and operation. Incorporating multiple materials is essential, yet challenging, in the bioprinting process to mimic the heterogeneous and anisotropic structure and properties of native tissue. This paper reviews the extrusion-based bioprinting process that employs varying approaches or mechanisms to print multiple materials and living cells, including side-by-side printing, core-and-shell printing, and recently developed advanced bioprinting methods. Key issues in this research area are also identified and discussed, along with recommendations for future research.