And with cell biology and tissue engineering, it is possible to grow just muscle and fat tissue. It’s called cultured meat. Scientists provide cells with the same inputs they need to grow, just outside an animal: nutrients, oxygen, moisture and molecular signals from their cell neighbors. So far researchers have cultivated bunches of cells that can be turned into processed meat like a burger or a sausage. This cultured meat technology is still in the early phases of research and development, as prototypes are scaled-up and fine-tuned to prepare for the challenges of commercialization. But already bioengineers are taking on the next tougher challenge: growing structured cuts of meat like a steak or a chicken cutlet.
What meat’s made of
If you look at a piece of raw meat under the microscope, you can see what you’re eating on the cellular level. Each bite is a matrix of muscle and fat cells, interlaced with blood vessels and enrobed by connective tissue. The muscle cells are full of proteins and nutrients and the fat cells are full of, well, fats. These two cell types contribute to most of the taste and mouth-feel a carnivore experiences when biting into a burger or steak. The blood vessels supply an animal’s tissue with nutrients and oxygen while it’s alive; after slaughter, the blood adds a unique, metallic, umami nuance to the meat. The connective tissue, composed of proteins like collagen and elastin, organizes the muscle fibers into aligned bundles, oriented in the direction of contraction. This connective tissue changes during cooking and adds texture – and gristle – to meat. The challenge for cellular agriculture researchers is to emulate this complexity of meat from the bottom up. We can grow muscle and fat cells in a petri dish – but blood vessels and connective tissue don’t spontaneously generate as they do in an animal. How can we engineer biomaterials and bioreactors to provide nutrient diffusion and induce organization so we end up with a thick, structured cut of meat?