The advent of 3D printing and stem cell research suggests that there will be a day when organ donors are no longer needed – we can simply manufacture our own in a laboratory. We’re a little way off from that hallowed age, however, and in the meantime, scientists are working on some potential alternatives.

For example, at present, we can certainly grow heart tissue in a laboratory setting, but these cells aren’t viable without a working blood supply – and that requires even more complex networks of tissue. So what do you do when you aren’t able to effectively grow blood networks from scratch?

One team from the Worcester Polytechnic Institute (WPI) have come up with a rather inventive way to supply the blood to a bunch of cultured heart cells, but it involved crossing over evolutionary kingdoms and looking to nothing less than the humble spinach plant for a bit of help.

“Plants and animals exploit fundamentally different approaches to transporting fluids, chemicals, and macromolecules, yet there are surprising similarities in their vascular network structures,” the team note in their Biomaterials study.

Using a novel detergent to remove the photosynthesizing material from their chosen spinach, the team were left with a near-transparent series of leaves with their vein-like vascular networks still intact.

They then infused the leaves with human heart cells, and within just a few days, these cells replicated, proliferated, and even began contracting spontaneously, just like they do in a normal human heart. The exchange of calcium ions – an important cell-to-cell communication tool that, among other things, keeps the heart beating – was also observed.

^{Using spinach to grow a heart part. WPI via YouTube}

At this point, the research is only at the proof-of-concept stage. A whole, functioning human heart has not been built out of spinach, but it’s a remarkable start to what could be an unorthodox future in artificial organ development. After all, spinach leaves are easily accessible, cheap to obtain, and the energy required to transform them into layers of heart tissue is surprisingly low.

The team explain that their research demonstrates the “potential of decellularized plants as scaffolds for tissue engineering, which could ultimately provide a cost-efficient, “green” technology for regenerating large volume vascularized tissue mass.”

Other teams across the world are working on their own methods for making notoriously tiny blood vessels. Last year, a group from Vanderbilt University in Tennessee managed to use a cotton candy machine to spin out microfibers of operating blood vessels – another wonderful example of scientists thinking way outside the box.