Fabrication of three dimensional (3D) organoids with controlled 
microarchitectures has been shown to enhance tissue functionality. Bioprinting 
can be used to precisely position cells and cell-laden materials to generate 
controlled tissue architecture. Therefore, it represents an exciting alternative 
for organ fabrication. Despite the rapid progress in the field, the development 
of printing processes that can be used to fabricate macroscale tissue constructs 
from ECM-derived hydrogels has remained a challenge. Here we report a strategy 
for bioprinting of photolabile cell-laden methacrylated gelatin (GelMA) 
hydrogels. We bioprinted cell-laden GelMA at concentrations ranging from 7 to 
15% with varying cell densities and found a direct correlation between 
printability and the hydrogel mechanical properties. Furthermore, encapsulated 
HepG2 cells preserved cell viability for at least eight days following the 
bioprinting process. In summary, this work presents a strategy for direct-write 
bioprinting of a cell-laden photolabile ECM-derived hydrogel, which may find 
widespread application for tissue engineering, organ printing and the 
development of 3D drug discovery platforms.