Cultured pork grown using the edible cell culture scaffolds. Credit: National University of Singapore
Lab-grown meat, also known as cultured or cell-based meat, is of growing interest for consumers concerned with animal welfare and the environmental impact of their food. The process of growing meat in the lab involves culturing skeletal muscle satellite cells from livestock animals onto scaffolds that are normally made from animal-based or synthetic materials, but these materials are often expensive or require subsequent separation from the cells in order to make the meat edible. To improve the cost-effectiveness and sustainability of lab-grown meat, researchers from the National University of Singapore (NUS) have developed a new plant-based, 3D-printable cell culture scaffold made from inexpensive and edible plant proteins.
The scaffolds were formulated from prolamins – plant storage proteins that are a common byproduct of starch and vegetable oil industries. The researchers experimented with different mixtures of zeins, hordeins and secalins, which are prolamins from corn, barley and rye, respectively. The mixtures were used as bioinks for high-precision electrohydrodynamic printing, a 3D printing technique commonly used in biomedical applications. The printed, structured scaffolds were examined using techniques such as scanning electron microscopy, as well as immersed in cell culture for seven days to determine their structural stability. The scaffolds were then used to grow tissue from porcine skeletal muscle cells, and the progress of cultures grown on different prolamin scaffolds were compared with those grown on standard synthetic polycaprolactone scaffolds.
The 3D printed scaffolds demonstrated good structural integrity in cell culture medium, although pores formed on the scaffold surface during the culturing of muscle cells. The researchers noted these pores are likely the result of enzyme secretion by the muscle cells, and could even potentially promote the growth of these cells. Zein/hordein and zein/secalin mixtures were found to have good printability and the scaffolds, printed in highly ordered tessellated structures, successfully supported the growth of the muscle cells with a maximum cell count after 11 days post-inoculation. Notably, the cells proliferated much faster on the plant-based scaffolds than on synthetic polycaprolactone scaffolds. Co-author Huang Dejian, deputy head of the NUS Department of Food Science and Technology, noted that the diverse peptides and functional groups present in the prolamins can aid in the attachment and differentiation of cells, giving them an additional advantage over synthetic options. Lastly, the team used a zein/secalin scaffold to produce a slice of meat from porcine cells with a similar texture and appearance to normal meat when colored with red beet extract. This research was published in Advanced Materials.
“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,” Huang summarized.
The researchers are working to refine their scaffolds, including by determining how particular scaffold structures and compositions affect the growth of animal cells and formation of muscle tissue. In the future, Huang noted, the safety, nutritional value and flavor of the meat will be important factors in potential commercialization.