Biophysicist turns asparagus into medical implants

His laboratory is filled with apples, asparagus, broccoli, celery, mushrooms, red peppers, strawberries and tomatoes. “Honestly, it looks like a farmers market,” says Andrew Pelling. “I’m not kidding… students just go to the grocery store and buy anything.

About 10 years ago, Pelling, a biophysicist, began to brainstorm with his team about materials that could be used to reconstruct damaged or diseased human tissue. Surrounded by a rainbow of fresh fruits and vegetables in his laboratory at the University of Ottawa, Pelling and his team dismantle biological systems, mix and match the pieces, and reassemble them in new and creative ways. It’s like a hacker who takes parts from a phone, computer, and car to build a robotic arm. Or like Mary Shelly’s Dr. Frankenstein, who built a monster out of corpses. Except that Pelling’s team turned an apple into an ear and, more recently, a piece of asparagus into scaffolding for spinal cord implants.

Pelling believes that the future of regenerative medicine – which uses external therapies to help the body heal, in the same way that a cut heals on its own or a broken bone can be mended without surgery – lies found in the produce aisle of the supermarket. He calls it “augmented biology,” and it’s much cheaper – thousands and thousands of dollars – than the implantation of organs donated by humans, taken from animals, or made or derived from humans. bioengineering from animal tissues.

A decellularized apple transformed into an artificial ear (right). Bonnie findlay

The seeds of Pelling’s inventions come from an unexpected source: the iconic musical and cinema Little shop of horrors. In the film, a large plant, Audrey II, comes to life and survives thanks to human blood. “I asked, ‘Could we grow Audrey II in the lab somehow? “, Says Pelling.

Well-funded scientists don’t usually spend their time recreating Hollywood props, but Pelling, who attended performing arts school as a child, describes it as “out of the way” for his lab. “Play is a key part of my science practice,” he says. “This is how I train my mind to be unconventional and creative.” He encourages his team to fool around and try out “weird biology.”

The plan to build Audrey II was to grow muscle cells on a scaffold of leaves and then grow a mouth. It did not work. At all. But Pelling says these kinds of “colossal failures” allow him to ask good questions and learn. The directive from his lab is to ask, “Can I change a cell’s environment and control its biology?” Audrey II’s failure left her wondering if muscle cells could not develop on the leaf because its waxy coating prevented it from decellularizing properly.

So Pelling went from plant leaves to production. “We spent two years messing around,” he says, decellularizing fruits and vegetables and growing mammalian cells in them. And, “it just kept on working, working, working. It was hard to find something that wasn’t working.

Decellularization as an implantation process is relatively new, developed in the mid-1990s mainly by Doris Taylor. By removing the genetic material that makes an apple an apple, for example, you end up with plant tissue, or a “cellulose mesh,” Pelling explains. “What we’re doing is removing all the plant DNA, the RNA proteins, all those kinds of things that can cause immune responses and rejection. And we just leave behind the fiber of a plant, like literally the stuff that gets stuck in your teeth.

Pelling seeding of mammalian cells on an apple-ear scaffold.
Pelling seeding of mammalian cells on an apple-ear scaffold. SAXX Underwear

When Pelling noticed the resemblance between a decellularized apple slice and an ear, he saw the true potential of his lab games. If he implanted the apple scaffolding in a living animal, he wondered, would it be “accepted” and vascularized? That is, would the body of the test animal spread over the plant cells as if it were not a dangerous foreign body and instead send signals to create a supply of blood, allowing plant tissue to become a living part of the animal’s body? The answer was yes. “Suddenly, and by accident, we have developed a material that has enormous therapeutic and regenerative potential,” Pelling explains. The apple ear does not allow hearing, it remains in the phase of animal experimentation, but it can have applications for aesthetic implantation.

Shortly after his groundbreaking apple experiment, published in 2016, which earned him the nickname “Mad Scientist,” Pelling focused on asparagus. The idea came to him while he was cooking. Looking at the end of a spear, he thought, “Hey, that looks like a spinal cord. What the hell? Maybe we can do something, ”he said.

When he photographed an asparagus spear in the lab, what he saw reminded him of blood vessels and the structure and organization of nerves and spinal cord. This led him to ask the question, “Can we use asparagus and their vascular bundles to grow a spinal cord?”

Scanning electron microscopy (SEM) images of the porous microstructure of decellularized apple tissue in which cells can grow.
Scanning electron microscopy (SEM) images of the porous microstructure of decellularized apple tissue in which cells can grow. Daniel Modulevsky / Pelling Laboratory

To find out, Pelling implanted decellularized asparagus tissue under the skin of a lab rat. In just a few weeks, blood vessels passed through the asparagus scaffold; the healthy cells of the animal moved through the tissue and transformed the scaffold into living tissue. “The surprise here was that the body, instead of rejecting this material, actually integrated into the material,” Pelling explains. In the world of bioengineering, achieving this has generally been a major challenge.

And then came the biggest surprise of all. Rats whose spinal cord had been severed and which had been implanted with the asparagus tissue were able to walk again just a few weeks after implantation. “I just remember… total shock,” Pelling said of the night his researchers texted him to come see the rats wandering around the lab. “I mean, an apple in one ear, whatever. But, like a walking rat. Like, come on! This must be nonsense … [So], we did it again, and again to convince ourselves of it.

While using asparagus tissue as a scaffold to repair the spinal cord isn’t a “silver bullet,” Pelling explains, it’s different from the types of implants that came before. Donated or manufactured organs are historically both more complicated and more expensive. Pelling’s implants were “made without stem cells, without electrical stimulation, without exoskeletons, or without any of the usual approaches, but instead using materials that were accessible at very low prices that we just honestly bought at the grocery store”, he said, “and we have reached the same level of recovery. (At least in animal testing.) Also, while patients typically need lifelong immunosuppressants, which can have negative side effects, to keep their bodies from rejecting an implant, this doesn’t seem necessary with Pelling’s herbal implants. And, so far, herbal implants don’t seem to break down over time like traditional spinal cord implants. “The inertia of plant tissue is exactly why it’s so biocompatible,” Pelling explains.

Apple-ear scaffolding in cultivation.
Apple-ear scaffolding in cultivation. Alexis williams

Originally, Pelling expected his asparagus experiments to be another of his blunders that lasted a few months. He believes he is able to push the scientific boundaries this way because he is a man. “I’m half Chinese, but I look like a white man,” Pelling says. “I am a man of science. I get away with more and I am subject to different standards.

In October 2020, the asparagus implant was named as a “breakthrough device” by the FDA. The designation means that human trials will be ramped up and will likely begin in a few years. If all goes well, Pelling is confident he’ll see humans walking around with asparagus scaffolds in their spinal cord long before 2040. Daniel Kraft, Chair of Medicine for Singularity University, whose background is in stem cell biology in regenerative medicine, describes the works as “refreshing”. It sparks a lot of imagination and inspiration.

Pelling, who calls himself a biohacker, says he will continue to push the boundaries. “What really interests me is if one day it will be possible to repair, rebuild and augment our own bodies with things that we make in the kitchen.”

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