English: Demonstration of heart injection of constructs in 11.5 dpc embryo. This video demonstrates the injection of a construct (marked by blue dye) into the left ventricle of the beating embryo heart at 11.5 dpc. After several heartbeats the dye can be seen in more distal parts of the embryo and finally in the head vein indicating successful injection. After injection the embryo is incubated with the heart still beating for 30 min before dissection for organ culture. For more detailed information see Fig. 1 and Materials and Methods.