Scientists are starting to grow meat the way farmers grow fruits. For thousands of years, people have raised animals for protein, but animal farming uses huge amounts of land and water and raises ethical questions about slaughter. To address these problems, researchers came up with a new idea: cultivated meat, which means growing muscle or fat cells from an animal until they form mature tissue.
It’s just that the planting environment is not the soil but the scaffold in a laboratory. The nutrients come not from fertilizers but from culture medium. Just as sunlight and temperature affect how fruits taste, the texture and flavor of cultivated meat depend on physical forces. The “chewiness” we talk about refers to hardness and elasticity, while the “fibrous texture” depends on how cells are arranged. These mechanical factors together shape the taste of meat1. In the laboratory, the muscle cells cultivated by scientists also need similar training. Lack of force stimulation will lead to disorderly and slowly growth.
How can we provide such stimulation? The most direct method is exercise. Aguilar-Agon et al.2 built a bioreactor to provide stretching for muscle cells in a certain cycle. This regular force made the cells thicker and stronger, increasing protein production and contraction force. This is similar to how fitness training makes muscles firmer. But exercise alone is not enough. Cells also need a place to attach and receive nutrients, that’s why we also need scaffolds. Scaffold is a sponge-like framework, which can provide supporting force for cultivated meat and help deliver nutrients; the perfusion process provides shearing force. Now we can use technologies such as Electrospinning, 3D bioprinting and plant decellularized matrix to manufacture scaffolds3.
A study discovered by Milae Lee et al., has found that the stiffness of the scaffold determines how cells behaved as muscle and fat4. On stiffer scaffolds (Young’s modulus around 11 kPa, similar to a rubber band), muscle cells tend to form myotubes, and the content of myosin and total protein significantly increase. High protein content allows you to smell a very delicious aroma when cooking steak. Fat cells, by contrast, prefer softer scaffolds (around 3 kPa, similar to jelly) and are more likely to form lipid droplets. To achieve the ideal ratio of muscle and fat, the stiffness of the scaffold must be balanced.
Priyatharshini Murugan et al.5 have used the natural vascular bundles of asparagus to create decellularized plant scaffolds with an elastic modulus of about 4.9 kPa, which falls within the ideal range for both muscle and fat growth. Pig muscle and fat stem cells can grow along the plant’s original channels, forming striped muscle fibers that are both aligned and elastic.
Cultivated meat is ultimately an art that combines biology and mechanics. The idea is exciting, but behind every gram of cultivated meat lie the high costs of scaffolds, culture media, and bioreactors6. One day, a steak on your plate might come from a lab. Before that happens, scientists need to keep balancing softness and strength, and must think about the challenges of large-scale production, cost balance, and food safety.