1. Introduction

The applications of 3D printing (3DP) in biomedicine vary with the ink materials and thus the final products. For example, prototyping fabricated from non-biocompatible plastic could be used in surgery planning or guidance. Another example is the 3D printed implants made of biocompatible but nondegradable materials, such as titanium. One more step further, researchers have applied degradable biomaterials to print implantable scaffolds that would guide the native tissue regeneration and thus achieve the ideal repair. What this thesis presents belongs to another stage, where cells and other biological elements are directly incorporated in the 3DP process to create a living product, which is termed as 3D bioprinting. This technology is supposed to lead to organ printing in the future, which might sound crazy but is actually happening.