This book highlights most advanced 3D printing techniques used for the manufacture of Bio-implants in regenerative medicine, the same behaviour these printed scaffolds have when they are biologically tested. For achieving scaffolds that can substitute the damaged tissue in order to heal the lesion and regenerate it at a speed compatible with the growth of the natural tissue, optimal 3D printing manufacturing parameters should be used and are described here. The combination of specific polymeric materials with metallic nanoparticles in the optimal concentrations are crucial to control scaffold mechanical properties. Material characterization and analytical techniques that allow studying these mechanical and biological properties are summarized too. A review of today and near future bio-implants that revolutionize surgery and regenerative medicine is presented.