Coloured scanning electron micrograph (SEM) of a bioprinted bone construct on day 13 of cultivation. It consists of a calcium phosphate bone cement (PBC, grey) and human mesenchymal stem cells (MSCs, blue) that have migrated from a hydrogel bio-ink. The calcium-phosphate bone cement was printed with a 3D printer and then a gel containing the MSCs was added, also by 3D printing. During cultivation the cells divide and migrate on the surface of the scaffold, building a dense network. Such cell cultures enable bone to be grown in the laboratory for implant into a patient. The picture was created as part of a cooperation with Quintessenz Publishing. Magnification: x1000 when printed at 15cm wide.