LAWN TO TABLE
NEW SYSTEM OF PRODUCING CULTURED MEAT SWAPS ANIMALS FOR BLADES OF GRASS
Paul De Bank looks at plants differently. When shopping at the supermarket or strolling through a meadow, he sees potential for producing new muscle tissue in the natural structures of the plant kingdom.
Elongated leaves of romaine lettuce with their pronounced ribs, long and slender celery stalks, or even blades of grass have aligned fibres that make them especially well-suited to being used as a scaffold: a structure used to grow cells.
The tissue grown on such scaffolds represents an intersection of food production and regenerative medicine: the engineered muscle could both hypothetically hit the grill for dinner, and be used to treat injury or disease.
In the early days of tissue engineering, the focus was on donor- or animal-derived organs. But there's so much more variety in plants, emphasizes De Bank, a professor in the University of Bath's Department of Pharmacy & Pharmacology who has worked in the field for 20 years.
Connecting the dots between the structures found within animal tissues and those in other kingdoms, he finds options wherever he looks.
“It's just using your imagination and what's out there, and looking at the natural world,” says De Bank. “If you walk around outside anywhere green, or in the supermarket, you see lots of fruit, vegetables, trees, bushes, and they've got all sorts of different shapes in them. And if you look at the cross section of wood and various plants, you have these different tubular structures and aligned structures that can be used to guide cell growth.”
Giving new meaning to “grass-fed,” De Bank and colleagues Prof. Marianne Ellis (a leading U.K. expert in cultured meat and cellular agriculture in the Department of Chemical Engineering) and Scott Allan (a PhD researcher in the Department of Chemical Engineering) have developed a lab system using blades of grass clipped from the university's campus to grow cultured meat.
In their study, which was recently published in the Journal of Biomedical Materials Research — Part A, the researchers show “that we can directly replace the animals with the grass they eat.” Cows would still be needed, explains De Bank, and be biopsied occasionally to generate cells, but there would be much less of a strain on both the animals and the environment.
“The beauty of it is, cows are very highly consumed,” says De Bank. “They eat grass and it squares the circle in that process by hopefully one day deriving a cultured meat product based on the foodstuff of the animals that I guess, in effect, we're saving.”
During two decades in tissue engineering, De Bank has done extensive work with scaffolds and modifying materials in order to elicit responses from cells. Applying these principles to food production seemed like a natural progression, he says, and many other tissue engineering labs have branched out into lab-grown meat as well.
In their work on transforming grass into cultured meat, the researchers were inspired by other tissue engineers using plant-derived scaffolds. De Bank mentions the Pelling Lab in Ottawa, led by biophysicist Andrew Pelling, where they have transformed apples into artificial ears and asparagus into spinal cord implants.
The edibility of the scaffold was key, says De Bank, “so we didn't have to grow the cells up, and then remove them from a non-degradable scaffold, and then form them into meat. We wanted something that we could grow the cells on without any further processing, and then use that to build it into cultured meat product.”
There are a number of challenges, he adds, and grass met their criteria in several ways. It's abundant, inexpensive, grows quickly and is easily harvested. It's also relatively simple to decelluralize (the process of emptying the native cells so they can be seeded with bovine stem cells, in the case of cultured beef), and though indigestible, grass is edible.
“We eat cellulose-based materials all the time, and we don't digest them, but we extract other nutrients,” says De Bank. “So it acts as the backbone for the generation of meat. We're not sure yet how palatable it would be; what the texture would be like. But it's a proof of concept that these plant-based structures can be used as a template for generating muscle.”
The flavour of the scaffold is likely to carry through to the cultured meat, De Bank says, but he's not sure what decellularized grass tastes like, if anything at all. The main potential issue with their grass-fed lab system could be texture — possible toughness — and he expects that this type of scaffold is well-suited to producing ground meat, not prime cuts.
If you look at a blade of grass, even with the naked eye, you can see the natural channels on its surface. This structure plays into another advantage grass presents as a scaffold: its stickiness. Plant-derived scaffolds often need to be modified in order to encourage cells to grow on them, but this wasn't the case with grass. The researchers found an adhesion rate of 35 per cent, which they considered a success.
“The channels that are naturally there in the grass scaffold did indeed cause the cells to line up, fuse together and form these muscle fibres that were all pointing in the right direction,” says De Bank. “The structure did its job.”
Advances in tissue engineering aren't restricted to the production of conventional animal proteins, De Bank emphasizes. There's a lot of interest in cultured insect muscle, for example, and fish — both of which require fewer resources to grow than mammalian cells.
Insect and fish cells thrive at lower temperatures (mammalian cells are grown at 37 degrees Celsius; insects 27 C; fish between 15 and 26 C) and may not need as many nutrients, making them a potentially more sustainable protein source, says De Bank.
As with cultured meat in general, he adds, widespread adoption will come down to perception and familiarity.
“I think people appreciate that we can't go on the way we are, so something needs to change. But the scientists and the engineers are trying to drive this forward: The technology is emerging and it exists now. But the adoption, I think, is up to the politicians rather than us — and the psychologists.”
WE CAN'T GO ON THE WAY WE ARE, SO SOMETHING NEEDS TO CHANGE.