Plant scaffolds developed for cultured meat

A research team from the National University of Singapore (NUS) has 3D-printed an edible cell culture scaffold using common plant proteins, allowing more sustainable lab-grown meat to be served on the table.

Cultured meat is growing in demand as environmental consciousness increases. It is produced by taking skeletal muscle cells from animals and growing them on three-dimensional constructs called scaffolds, which provide structural support as the cells multiply and develop into tissues.

Typically, the scaffolds are made from synthetic or animal-based materials, which are both expensive and inedible. The researchers, led by Huang Dejian, Deputy Head of the NUS Department of Food Science and Technology, looked into plant proteins, which are biodegradable and biocompatible with animal cells. They also satisfy requirements for food consumption, making them suitable for culturing meat.

“By using readily available cereal prolamins as biomaterials for high-precision 3D printing technology, we open up a new method for manufacturing edible and structured scaffolds to produce cultured muscle meat slices with fibrous qualities,” Dejian said.

The researchers developed the scaffold using prolamins, a family of plant storage proteins that, due to their specific amino acid profile, have low nutritional value. Prolamins are usually generated as waste in the starch and vegetable oil industries, making them a sustainable resource. The researchers used mixtures of prolamins derived from corn, barley and rye flour, which acted as the ink for electrohydrodynamic printing, a high-precision 3D printing technology commonly employed in biomedical applications.

To assess whether the prolamin constructs were fit for meat cultivation, they were submerged in the cell culture medium and inspected seven days later to examine any structural changes. Under a scanning electron microscope, the scaffolds held their structure and did not collapse, though multiple holes did develop on their surfaces. According to the researchers, however, these pores are more likely the result of enzymes secreted by the cultured cells rather than evidence of structural weaknesses.

Scaffolds must be biocompatible with muscle cells from agricultural animals to be useful in cultivating meat, meaning they need to be able to accommodate these cells and support their growth and development.

To test this, the researchers seeded the prolamin constructs with stem cells from pig skeletal muscle and measured cell proliferation over the following days. They found that the cells divided extensively on the scaffolds, reaching a maximum count 11 days after they were inoculated. When compared against a standard scaffold, the pig cells seeded onto the prolamin constructs proliferated much faster.

“Scaffolds made from plant proteins are edible and have diverse and variable peptide sequences that can facilitate cell attachment, induce differentiation and speed up the growth of meat. In contrast, synthetic scaffolds such as plastic beads used for cultured meat have no functional group, which makes it difficult for animal cells to attach and proliferate. In addition, synthetic scaffolds are not edible and extra steps are required to separate the scaffolds from the meat culture,” Dejian said.

As a proof of concept, the researchers developed an actual slice of meat by culturing pig skin stem cells on a plant scaffold and allowing them to mature into muscle. The experiment turned out to be a success. Within 12 days, the research team was able to culture meat that was similar in texture and overall appearance to real animal meat.

The researchers are working on refining the technology. Further study is needed to better determine how the structure and composition of the prolamin constructs might impact the growth of animal stem cells and how they form muscle tissue.

“Moreover, we need to ensure the resulting meat products are market-ready, with safety profiles that will satisfy rigorous regulatory demands and nutritional compositions that will fulfil recommended dietary needs,” Dejian said.

Cultured pork grown using the edible cell culture scaffolds. Image credit: NUS