This article explains a theoretical limb regeneration process being developed by bioengineer Michael Levin. Read our profile of him here.
Surgeons prepare an amputation site for limb regeneration by cleaning the wound site of debris. They then expose raw nerves, bones, tendons, muscles, and other tissues so the molecules in them can be treated with a faint electrical charge
To conduct electrical currents, the wound site must remain moist and protected from air, which would dry it out and expose the wound to infection. So surgeons put this sleeve over the site. Made of silicone, rubber, and silk, it mimics the aquatic habitat of a womb.
The sleeve contains drugs that can manipulate the body’s ion channels, hollow proteins that sit on the surface of cells letting charged molecules move in and out, thus changing a cell’s charge and its signaling to other cells across the body.
The cells’ bioelectric signals influence the action and direction of genes, acting as a sort of software code for the entire body. Once the signal to divide cells is given, a cascading effect happens, and the body will begin the natural process of growing an arm.
The process is as fast as normal human fetal growth. That means a 25-year-old solder who lost an arm to a roadside bomb would have to wait a decade, until the age of 35, for the arm of a middle-schooler—but one that would be fully functioning.
This article was originally published in the Popular Science, January/February 2017 issue of under the title “How To Grow An Arm.”