German researchers have developed an artificial cornea that promises easy integration with a patient’s native cornea, and prevents cellular hyperplasia on its plastic surface:
“Our artificial corneas are based on a commercially available polymer which absorbs no water and allows no cells to grow on it,” says IAP project manager Dr. Joachim Storsberg. “Once our partner Dr. Schmidt Intraokularlinsen GmbH has suitably shaped the polymers, we selectively coat the implants: We lay masks on them and apply a special protein to the edge of the cornea, which the cells of the natural cornea can latch onto. In this way, the cornea implant can firmly connect with the natural part of the cornea, while the center remains free of cells and therefore clear.” What is special about this protein is that it can survive the later thermal sterilization of the artificial cornea without being damaged, as it does not have the three-dimensional structure typical of large proteins. Such a structure would be destroyed during the sterilization process, leading to changes in the material’s properties. The optical front part of the implant is coated with a hydrophilic polymer, so that it is constantly moistened with tear fluid.
Researchers in Dr. Karin Kobuch’s working group at Regensburg University Hospital have already tested these corneas in the laboratory and found that their cells graft very well at the edge and cease growing where the coating stops. The optical center of the implant thus remains clear. The first implants have already been tested in rabbits’ eyes – with promising results. If further tests are successful, the technology will be tried on humans in 2008.
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