Reviewing In-Vitro Tissue Engineering Research:
Growing food in animals is the most inefficient way to feed 7 billion people. In the next years, the demand for meat, eggs and dairy are going to grow 50%. A rate of demand we can’t presently sustain with animal-based food production. This way of production is deadly and environmentally detrimental, and additionally, it is wasteful and an incompetent use of resources.
There is ongoing research towards options of meat alternatives using in vitro production. It is clear that using animals to produce food has many downsides (unsustainability, inefficiency, unethicality, etc.) and few upsides (it employs lots of people). Introducing an in-vitro form of meat production will harness a meat alternative that allows humans to stop being murderous animals, but also solve some big issues like contribution to climate change and incompetent distribution of resources.
A research paper, by Zuhaib Fayaz Bhat and Hina Fayaz, does a really great job in outlining the need for cultured meat (aka clean meat), steps of culturing cells using tissue engineering techniques and challenges within the field. Here’s the link:
The paper goes into depth describing how we can actually culture meat using cells. Further, it outlines different approaches to create in vitro meat, such as using myosatellite cells or embryo cells. Myosatellite cells are adult stem cells that come from the muscle from the animal. When they’re proliferated (grown) they can only produce more muscle cells. Their downside is they do not have unlimited regenerative power. On the other hand, embryo cells are pluripotent stem cells and can essentially regenerate indefinitely. Since they’re pluripotent, they have the ability to become any cell in the body of an animal, however, this trait isn’t helpful for clean meat. We only need muscle cells.
Using the two possible cell sample approaches ( Embryo or Myosatellite (skeletal muscle) cells), the paper describes, in detail, the processes the cells go through to end up becoming edible products.
Cultured meat works by taking either embryonic stem cell sample or myosatellite skeletal muscle cell samples from an animal. In order to get the stem cells, animals go through a small, painless and fast procedure to gather the sample. They’re still contributing to the food chain, technically, but painless stem cell sample for the name of science is a lot better than getting slaughtered !!!
Embryonic (or pluripotent) stem cells are stem cells that can basically become any cell they want and they can regenerate indefinitely (given there are no genetic mutations)
Myosatellite skeletal muscle cells are adult stem cells, meaning they can’t regenerate into different types of cells. Myosatellite skeletal muscle cells come from the muscle of an animal, and they can only regenerate to be muscle cells. (They can’t regenerate indefinitely).
So technically, if we used embryonic cells (which regenerate indefinitely) 1 cell could produce meat for everybody. At this moment, the technology isn’t advanced enough to use embryo cells because it isn’t guaranteed that they’ll always form muscle cells (right now for lab-grown meat all we need is muscle). Fingers crossed they’ll find future implications of embryo cells in the lab-grown meat world! But currently, cultured meat will use Myosatellite Muscle Cells
Once we have the stem sample, these cells are turned from stem cells (potential muscle cells) into myoblasts (actual muscle cells). We do this by placing the myosatellite cells in a medium. The medium has a serum that provides the cells with all the essential nutrients it needs to grow. It essentially “feeds” the stem cells so they can grow, as if they were in the body of the animal.
Then the cells proliferate and produce more and more cells. (The process of putting live cells on a nutrient-based medium is called explanting.) Once the stem cell samples are explanted onto the medium, they are able to grow into myoblasts.
The myoblasts then form multinucleated myotubes (muscular tissue), through a process called myogenesis. Tissue engineering and scaffolds make this happen. What occurs is the myoblasts form myotubes on collagen microspheres. This technique will be described later on. Microspheres are small circular particles that contain the protein of collagen.
Myotubes are basically a more tense version of myoblasts. They’re the beginning formation of muscle. By existing around the collagen microspheres, myoblasts are able to collide into myotubes. This process is very natural for cells, especially when they have scaffolds (which will be discussed later on:) so little scientific guidance is required.
The myotubes are then places in a bioreactor tank where they differentiate (change)into microfibers. When the cells fuse into microfibers, they can then be cooked, harvested and consumed like regular meat.
Now we have real animal muscle created from real animal cells, made without animals.
Other papers analyzed to compile the in-vitro meat production process include:
The Design of Scaffolds for Use in Tissue Engineering. Part I. Traditional Factors | Tissue…
In tissue engineering, a highly porous artificial extracellular matrix or scaffold is required to accommodate mammalian…
The Basics of Tissue Engineering and Scaffolds
Tissue engineering is used during the process to mimic neo-organogenesis. Neo-organogenesis is a process in biology where embryonic cells develop and form organs. When we create lab-grown meat, we’re culturing young stem cells to become muscle cells and eventually form muscle (an organ) as if they were in an animal. If we use tissue engineering methods, we can mimic the conditions regular stem cells develop inside animals during their embryo (early) development stage.
Tissue engineering has many uses, including producing new, functioning organs, bone creation and advanced drug testing. Tissue engineering is also employed in in-vitro cell culture, but the main goals when engineering the cells in cultured meat is to create tissues that taste good and behave like meat, unlike in organ tissue engineering, where the muscles must be engineered to function in the human body. Although they use the same type of engineering process, the objectives vary.
Tissue engineering is really revolutionary. We’ll be able to create synthetic hamburgers and hearts.
Culturing meat uses artificial scaffolds and scaffold-based tissue engineering strategies.
Well… What’s a scaffold?
They’re replacements for extracellular matrix (ECM)
But…What’s an ECM??
Every living thing is made up of cells. Basically, all cells are attached to ECMs. It’s where they migrate, providing cell support, regulating intercellular communication, grow, proliferate, etc. Without ECMs, cells wouldn’t be able to go through mitosis or meiosis (the processes of the production of new cells), cells wouldn’t be able to communicate or move around, etc. Since we’re all made up of cells, without ECMs, we wouldn’t be able to function, so ultimately nothing would be living.
Extracellular matrixes are made up 3 main components:
- Proteoglycans (proteins with glycosaminoglycan (carbohydrates whose molecules have lots of sugar molecules bonded together) groups) which cushion cells
- Insoluble collagen fibres which give cells resilience and strength
- Soluble Multi adhesive extracellular matrix proteins which essentially bind the proteoglycans and collagen fibres to receptors on the cell.
Different ratios and types of these three components make different extracellular matrixes tailored to different cells and functions. (Note: proteoglycans and ECM proteins are just categories of component types, multiple materials can be a proteoglycan or ECM protein)
Woah, that’s a lot to take in. Let’s summarize: ECMs are the reasons our cells can function and are used to direct cells in our bodies. And scaffolds are artificial ECMs used for in-vitro production of cells.
ECMs let cells do many functions. Without them, cells wouldn’t exist. In animals, we have ECMs, so we can generate organs and muscles. The aim of lab-grown meat is to grow muscle (that can eventually be consumed) outside of an animal. Inside, for example, a cow, there are ECMs that can direct muscle cell growth. But using cellular agriculture, we need to use scaffolds.
Scaffolds are porous materials used to guide the growth of cells and are necessary for any type of tissue engineering. As of now the materials used for scaffolding are less than ideal, but we’re still looking. In cultured meat, a typical scaffold material used is collagen microspheres which turn the stem cells into myotubes.
Although scaffold materials are not perfect, they’re necessary for any tissue engineering.
This research paper, presented by Fergal J. O’Brien, outlines what scaffolds are and their use in Tissue Engineering (TE). Current means of tissue engineering research is levitated towards human, medical uses, however, the same principles of TE still apply to meat culture.
Biomaterials & scaffolds for tissue engineering
Every day thousands of surgical procedures are performed to replace or repair tissue that has been damaged through…
The transportation industry accounts for about 14% of greenhouse gas emission, while the agriculture industry accounts for 18%. Meat and animal byproduct production account for more greenhouse gas emissions than transportation.
Good thing we already have a solution: Cultured meat. For the time being, it’s not actually a product. The first lab-grown burger cost about $300,000 to make, and it wasn’t perfect, but we still made it and proved it theoretically was possible. Since then, we’ve come a long way in the process of creating lab-grown meat.
Price Point Hurdles: The Serum
In order to turn the original cell sample into myoblasts, we need a medium that can provide the cells with nutrients. Right now, the current medium being used is the very expensive: fetal bovine serum (unborn cow blood). Currently, there is research being done to find alternative serums and plant-nutrient-based mediums that can be used to grow the stem cells into myoblast (muscle cells), this will significantly lower the cost of production, and lower the price of the sale. Finding a good plant serum to grow these cells in that maximizes proliferation is critical to progressing cultured meat technology.
At this point, fetal bovine is the most successful and tasty. But it’s hoped that in the future there’ll be an alternative that could make lab-grown meat as tasty, but cheaper.
But What Will the Consumers Think?
Synthetic meat is undoubtedly going to hit (and hopefully disrupt) the market. So many researchers are looking into it, and the technology is being evolved. But there are still raising concerns whether or not this technology will actually be accepted if the could make in-vitro meat taste good and priced comparable to other meat products (two of the biggest concerns with the product. )
The largest concern marketers have is the transparency of lab-grown meat: will people trust it?
This research paper, by Mark J. Post, outlines the conflicts of the Cultured Meat Market:
Cultured meat from stem cells: Challenges and prospects
The key takeaways from this paper :
In-vitro production of meat is beneficial for eliminating slaughter, can improve the safety and health of products and produces a lower environmental footprint than traditional meat production.
However, the corresponding challenges include transparency, technology acceptance and consumer resistance.
It’s hard to predict the reputation of a theoretical product. According to the study, a minority of people were completely opposed to rejecting the product. The largest concern was whether or not synthetic meat would lead to resistance and evoke thoughts to the consumers.
It’s predicted that if suppliers can create lab-grown meat at a strong market price, and at a respectable taste, it has a chance to survive and disrupt the market.
This is essentially a summary of my past month’s research on in-vitro meat, consumer opinions and scalability, and tissue engineering. If you have any questions, feel free to reach out to me on LinkedIn or Twitter.