Researchers in the Center for the Science and Engineering of Materials (CSEM) at the California Institute of Technology are developing a new class of biomaterials for use in surgery and regenerative medicine. These new materials are produced by genetic engineering, and consist of pieces of natural proteins that have been stitched together in new ways to allow control of both their mechanical properties and their interactions with cells and tissues after surgical implantation. In collaboration with researchers at the University of California, San Francisco, and at Calhoun Vision, Inc., CSEM scientists are exploring the use of their materials in eye surgery. The figure shows a protein lens that has been surgically implanted into the cornea of a rabbit eye; the green dye allows researchers to monitor the rate at which the cornea heals over the lens to incorporate the implant into the corneal tissue. The figure on the left shows the exposed lens immediately after surgery; that on the right shows the fully healed cornea after seven days. Procedures such as this might one day allow surgical correction of corneal defects caused by injury or disease, and might replace eyeglasses, contact lenses, or LASIK surgery as means of correcting less-than-perfect vision.