How Scientists Turned a Spinach Leaf Into Beating Heart Tissue

Researchers at the Worcester Polytechnic Institute saw more than salad when they studied spinach leaves. (Photo: Johan Nilsson/Unsplash)

Our relationship with the world of plants may soon be a lot more intertwined than any of us could have imagined.

Researchers at Worcester Polytechnic Institute in Massachusetts have effectively hacked a spinach leaf to function as living, beating human heart tissue. The proof-of-concept is so bewildering that it demands viewing via the video above before further explanation.

So how did they pull this off — and why?

The inspiration ironically came while WPI bioengineers Glenn Gaudette and Joshua Gershlak were enjoying some leafy greens at lunch. According to the Washington Post, the pair had been brainstorming ideas to help solve the country's widespread organ donation shortage. Despite advancements in the engineering of artificial tissues, it's not yet possible to recreate the complex network of blood vessels that transport vital nutrients and oxygen to surrounding tissues.

Instead of trying to solve this obstacle, the researchers decided to leverage what had already been perfected in the leaves of the spinach plant.

"Plants and animals exploit fundamentally different approaches to transporting fluids, chemicals, and macromolecules, yet there are surprising similarities in their vascular network structures,” the authors wrote in a paper published in the journal Biomaterials. “The development of decellularized plants for scaffolding opens up the potential for a new branch of science that investigates the mimicry between plant and animal.”

To transform the spinach leaf into a repurposed slice of beating heart tissue, the team first stripped away the plant's cells using a common detergent. Once removed, all that was left was translucent cellulose and a network of veins. They then seeded the cellulose with muscle cells which, after five days, began to beat on their own.

“It was definitely a double-take,” Gershlak said of the spinach leaf's transformation. “All of a sudden you see cells moving.”

To prove they had a viable transport system to nurture the cells, the team added red dye to the top of the leaf and watched in amazement as it was pumped through the vascular network. They also injected the leaf with beads the size of red blood cells to confirm that molecules could be pushed through the veins.

“I had done decellularization work on human hearts before," Gershlak said in a statement, "and when I looked at the spinach leaf, its stem reminded me of an aorta. So I thought, let’s perfuse right through the stem. We weren’t sure it would work, but it turned out to be pretty easy and replicable. It’s working in many other plants.”

While such a breakthrough is still in the early stages, the team envisions a day when plant cellulose might be used to repair damaged organ tissues.

"Since a wide variety of anatomical structures exist within the plant kingdom, finding structures with mechanical properties emulating those needed for a human tissue engineered scaffold, even after decellularization, should be feasible," the authors wrote.