Scientists have been able to turn spinach leaves into working heart tissue, with a technique that could in future help heart attack patients. It is hoped that if enough tissue can be grown in enough size, the technique could treat many injuries. Plants and animals transport substances around the body very differently but it is the network of tiny blood vessels or capillaries which are quite similar. Using spinach, the researchers found a way to recreate tiny networks of blood vessels that branch through human tissue, something that 3D printing has not yet been able to achieve. Researchers at Worcester Polytechnic Institute stripped the spinach leaves of their plant cells using a detergent and then injected a blood-like substance into the leaf’s capillaries to culture beating human heart cells.