Electrical pulses, biochemical signals and pharmaceuticals have all been used to produce reactions in the tissue that show it behaves in the same way that natural human muscles does. As a result, laboratory grown tissue may soon provide researchers with the ability to study diseases and assess drugs without invasive procedures on human subjects.

In a study headed by Nenad Bursac, associate professor of biomedical engineering at Duke University, and Lauran Madden, a postdoctoral researcher in Bursac's laboratory, the team began by using a sample of human cells that had already been grown beyond the stem cell stage, but had not yet formed into muscle tissue. These "myogenic precursors" (that is, cells that will become muscle tissue) were then stretched by the researchers over a supportive scaffolding designed to promote their growth in 3D and to increase their area to more 1,000 times their original size.

Molded from PDMS (silicone), the entire structure was filled with a growth medium that allowed the cells to develop while the structure itself helped to form aligned and functioning muscle fibers. As a result, the team was able to grow around 5 grams of muscle tissue for every 50 mg of donor tissue – a hundred-fold increase in mass.