Breakthrough Achieved in Developing In Vitro Meat12 August 2013
Last week, Prof Mark Post from Maastricht University unveiled his creation of in vitro meat – a beef burger manufactured out of stem cells that was cooked at a glittering launch and eaten by a Chicago food writer and an Austrian food researcher, Josh Schonwald and Hanni Rützler.
Mark Post (pictured) is Professor of Vascular Physiology and Tissue Engineering at Maastricht University, Faculty of Health, Medicine and Life Sciences.
He launched his project with the aim of creating an edible hamburger from stem cells (‘in vitro meat’) in October 2011.
The project is a continuation of a 2004 study funded by the Dutch government to the amount of €2 million.
The study, initiated by W. Van Eelen, was implemented by a consortium of three universities (UvA, UU and TU/e) and an industry representative, Meester Stegeman BV.
The University of Amsterdam primarily focused on the development of efficient growth media, while the University of Utrecht focused on the isolation of stem cells and their proliferation in muscle cells.
Prof Post, then a part-time professor at the Eindhoven University of Technology, and his research team developed a method to ’train’ the muscle cells, in terms of size, not number, through electrical stimulation.
The study was finalised in 2009 with tangible results. The researchers were able to cultivate 8x22 mm pieces of meat of 0.5 mm thickness from the muscle stem cells of mice, consisting of millions of cells.
The researchers say that there are several crucial steps in the development of ‘cultured meat’.
The first step is to extract muscle stem cells from animals, usually cows, pigs or chickens. This project uses stem cells obtained from little pieces of fresh cow muscle for instance obtained through biopsy.
The cells must then multiply, which requires a growth medium. This project uses and has experimented with commercially available media, supplemented with calf serum.
Three culture dishes, each with a strip of muscle anchored between pentagonal anchors made of Velcro
In the next stage, researchers at the University of Amsterdam worked with synthetic mediums or simple and efficient nutrient sources such as algae extracts.
The isolated stem cells then have to develop into muscle cells. Because the stem cells are designated muscle precursor cells, this process largely happens automatically.
As with natural muscle cells, the cultivated muscle cells ‘bulk up’ into solid muscle fibres/bundles. To do so, they are affixed to a soluble polymeric sugar scaffold and trained by building tension between two anchor points in the bioreactor. This also largely occurs spontaneously.
Electrical stimulation of muscle cells (left panel) matures early muscle cells (middle panel) into mature skeletal muscle which shows typical transverse striations (right panel, arrows) based on abundance of contractile protein units.
As soon as the muscle cells grow in size, it is important that the tissue is continuously supplied with nutrients. For the small, newly formed muscle strands, regularly changing the culture medium suffices.
Creating larger slices of meat, however, requires the creation of soluble polymer (sugar chain) duct systems through, which a medium can flow, similar to the way blood flows through the veins.
To make the tissue edible, taste and texture must be just right.
This should be achieved by recreating the natural consistency of meat in terms of protein composition, fat tissue, etc.
If this does not produce the desired result, accepted food technology methods are used to improve the taste and texture of the meat.
At the end of this process, the final result is edible muscle tissue that can be ground to create minced meat and, ultimately, a hamburger
Researchers are currently working on enhancing production using existing techniques.
Two new projects will soon be launched to cultivate fat tissue and enhance the expression of myoglobin in meat - the oxygen-binding protein found in muscle tissue.
The ‘in vitro meat project’ team consists of Prof Mark Post and two technicians.
The project is fully backed by Sergey Brin to realise the first lab-grown burger.
“There are basically three things that can happen going forward. One is that we all become vegetarian. I don’t think that’s really likely. The second is we ignore the issues and that leads to continued environmental harm, and the third option is we do something new,” said Sergey Brin.
“Sometimes when technology comes along, it has the capability to transform how we view our world. I like to look at technology opportunities. When technology seems like it is on the cusp of viability and if it succeeds there, it can be really transformative for the world.”