PERMA-HAND Suture is a nonabsorbable, sterile, surgical suture composed of an organic protein called fibroin. This protein is derived from the domesticated species Bombyx mori (B. mori) of the family Bombycidae. Silk for braided sutures is processed to remove the natural waxes and gums, coated with a special wax mixture, and is available undyed and dyed black.