Scientists at at Worcester Polytechnic Institute have successfully managed to grow human heart cells on a scaffolding made from spinach leaf. How? First, they dissolved the leaf’s cellular material using detergents, leaving the cellulose background behind. Once completed, they added human heart cells and got them to adhere to the structure. These cells could still beat the way a normal heart should, while the vasculature could support blood flow. Click here to view the first image in today’s viral picture gallery. Continue reading for the five most popular viral videos today, including one of a device that turns air pollution into ink.