Bio-compatible polymer holds promise for artificial cornea
01 October 2012
Corneal transplants are often not possible because of lack of donors. In the future, an artificial cornea could make up for this deficiency.
Thousands of people lose their eyesight due to damages to the cornea, such as trauma, absent limbal stem cells or diseases. Transplantation of a donor cornea is the therapy of choice for a great number of those patients. Let alone the issue of scarce donor material, a sub-group of patients do not tolerate transplanted corneas, necessitating the employment of an alternative means of restoring eye sight.
In close cooperation with the Aachen Centre of Technology Transfer, Dr Joachim Storsberg and his team from the Fraunhofer Institute for Applied Polymer research IAP in Potsdam, are attempting to improve upon this by developing an artificial cornea. Scientific partners in the 'ArtCornea' project include the Martin Luther University of Halle-Wittenberg, ACTO e. V. and the Ophthalmic Clinic Cologne-Merheim.
“We are in the process of developing two different types of artificial corneas," says IAP project manager Dr Storsberg. "One of them can be used as an alternative to a donor cornea in cases where the patient would not tolerate a donor cornea, let alone the issue of donor material shortage.”
ArtCornea is based on a polymer with high water-absorbent properties. Dr Storsberg and his team have added a new surface coating to ensure anchorage in host tissue and optical functionality. The haptic edge was chemically altered to encourage local cell growth. These cells graft to the surrounding human tissue, which is essential for anchorage of the device in the host tissue.
The researchers aimed to enlarge the optical surface area of the implant in order to improve light penetration beyond what had previously been possible – a tall order. “Once ArtCornea is in place, it is hardly visible, except perhaps for a few stitches. It’s also easy to implant and doesn’t provoke any immune response,” says Storsberg, highlighting the merits of this new development.
The specialists have also managed to make a chemically and biologically inert base material biologically compatible for the second artificial cornea, ACTO-TexKpro. Dr Storsberg achieved this by selectively altering the base material, polyvinylidene difluoride, by coating the fluoride synthetic tissue with a reactive molecule. This allows the patient’s cornea to bond together naturally with the edge of the implant, while the implant’s inner optics, made of silicon, remain free of cells and clear.
The ACTO-TexKpro is particularly suitable as a preliminary treatment, for instance if the cornea has been destroyed as a consequence of chronic inflammation, a serious accident, corrosion or burns.