In a creative display of bioengineering, a team of researchers used a plant's vascular system to scale up reproducing human tissue. Like with most recent bioengineering, the team from Worchester Polytechnic Institute found inspiration from nature. They used spinach leaves to grow beating human heart cells.
[Image source: Worcester Polytechnic Institute]
A major problem for researchers comes from scaling up regeneration, taking those small lab samples and making full-sized tissue. A problem compounding the issue is how to develop the vascular system to handle the developing tissue. Current methods -- including the ever-popular 3D printing -- can't make the tiny capillaries needed. Researchers had to develop a network so intricate that it could deliver the oxygen and nutrients to the tissue as naturally as possible. For the team at WPI, the link between the small capillaries of plants and the human cardiovascular network seemed obvious.
"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. "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."
First, the team stripped spinach leaves of plant cells and replaced them with those from the human heart. They sent fluids similar to human blood through the veins of the leafs. Then they seeded the spinach veins with human cells found along blood vessels. The empty spinach veins provided enough support to handle the human cells.
Stripping a spinach leaf through decellularization. This is done using a detergent.
[Image source: Worchester Polytechnic Institute]
The team hopes this research could be used to help treat heart attack patients. The concept of stripping plant cells and replacing them with human cells could also open doors for further study. Biomedical engineering professor Glenn Gaudette said this then could lead to unexpected breakthroughs.
"We have a lot more work to do, but so far this is very promising," the Massachusetts professor said. "Adapting abundant plants that farmers have been cultivating for thousands of years for use in tissue engineering could solve a host of problems limiting the field."
The team's paper also elaborates on the hope that plant-based engineering offers:
"By exploiting the benign chemistry of plant tissue scaffolds, we could address the many limitations and high costs of synthetic, complex composite materials. Plants can be easily grown using good agricultural practices and under controlled environments. By combining environmentally friendly plant tissue with perfusion-based decellularization, we have shown that there can be a sustainable solution for pre-vascularized tissue engineering scaffolds."
The project also serves as a great reminder of the need for interdisciplinary research. The team includes biotechnicians, molecular specialists, and engineers.
"When you have people with different expertise coming at a problem from different perspectives, novel solutions can emerge," said Gaudette.
The team is continuing to work on how to best scale up the stripping process. They're also observing how other types of human cells grow using plant structures. They look to engineer another vascular network for releasing blood as well.
The team published the full research online in the journal Biomaterials.