In bone tissue engineering (BTE), 3-D printing is a reliable and customizable method used to repair bone defects by producing biomimetic tissue scaffolds. In a recent study published online on Tissue Engineering Part A (Mary Ann Liebert, Inc), Qing Li and a team of scientists engineered a biomimetic substitute closest to the natural bone structure and composition for bone grafting. For this work, they used two different types of hydroxyapatite (HA) materials: nanohydroxyapatite (nHA) and deproteinized bovine bone (DBB) dispersed into collagen (CoL) to prepare a bio-ink and engineer composites of nHA/CoL and DBB/CoL as 3-D printed scaffolds.