When a person has a heart attack, a portion of the heart dies. We are interested in creating thick engineered heart tissue with blood vessels that can be used as a bandage on the heart to help repair the damaged tissue. This image shows the cross section through a 3D polymer scaffold that we created (blue) that holds both heart cells (red) and vascular cells (green). Though the heart cells were placed on the top of the scaffold and the vascular cells were placed on the bottom of the scaffold, this image shows that they are moving towards each other during co-cultivation with fluid flow in the lab.