For a millennium, traders brought silk fabrics from the Far East along the Silk Road to Europe, where the beautiful yet tough material was fashioned into dazzling clothes. Today bioengineers are infusing the natural protein fibers spun by silkworms with enzymes and semiconductors. They are processing the modified strands under varying temperature, shear and acidic conditions to create novel materials with remarkable properties.
Physicians like silk sutures because they are strong and compatible with human tissue, meaning the body’s immune system doesn’t reject them. Our laboratory at Tufts University has recently extended those traits to make thin tubes that can be used as grafts to replace sections of clogged arteries, which could eliminate the need to extract a vein for that purpose from a patient’s leg for a coronary bypass, the usual procedure. James Goh and his colleagues at the National University of Singapore have regenerated an anterior cruciate ligament in a live pig’s knee using stem cells implanted in silk scaffolding.