Researchers have gotten pretty good at growing human tissues from stem cells—from heart cells in a Petri dish to 3-D printing full ears. But assembling the complex vascularity of heart tissue is no small feat. Even the most sophisticated 3-D printers can't fabricate the structure. However, as Ben Guarino writes for The Washington Post, researchers at Worcester Polytechnic Institute might have a solution: use spinach leaves as the backbone for the heart tissue.
The study, recently published in the journal Biomaterials, offers an innovative way to solve a common problem in tissue engineering by looking toward the plant world. Though plants and animals transport fluids in very different ways, their vascular structures are similar, according to a press release.
Take a plant leaf and hold it up to the light. "What do you see?" Tanja Dominko, an author of the study, asks Cyrus Moulton at the Worcester Telegram. "You see a plant vascular system that is very, very similar to a human system and serves an identical purpose,” she says.
But to use that structure, researchers had to first remove the plant cells, leaving its vascular system intact. To accomplish such a feat, the team washes the leaves through using a type of detergent, turning the leaf from transparent green to translucent white. The remaining cellulose structure is compatible with human tissue.
As Guarino reports, the researchers then seeded the spinach with cardiac tissue, which began to grow inside the leaf. After five days, they witnessed some of the tissue contracting on the microscopic level. In other words, the spinach leaf began to beat. They passed liquids and microbeads the size of human blood cells through the leaves to show they could potentially transport blood.
Though the team wasn't aiming to grow a full heart from spinach, they hope the method could be used to help patients after suffering from heart attack or other heart problem. “Long term, we’re definitely envisioning implanting a graft in damaged heart tissue,” Glenn Gaudette, a bioengineer and co-author of the study, tells Guarino. They hope to make a patch as thick and strong as natural heart tissue.
Spinach is not the only superfood the team is working with. According to the press release, they have also successfully removed the cells from leaves of parsley, sweet wormwood and hairy peanut root. In the future, different plants could be used as scaffolding to grow different patches and replacement parts. For instance, the hollow stem of jewelweed could be sued to create arteries and wood or bamboo could be used to engineer bone. “When you think of the wide array of plants out there, there’s almost nothing that plants can't do,” Gaudette tells Moulton.
The Worcester team isn’t the only group working on this idea either. Andrew Pelling at the University of Ottawa is using the cellulose in apple slices to grow (slightly scary-looking) human ears.