Christine Radtke, a Professor for Plastic and Reconstructive Surgery at Austria’s MedUni Vienna/Vienna General Hospital, has 21 spiders. The silk obtained from the Tanzanian golden orb-weavers offers Radtke and her team a valuable material to repair nerve and tissue.
As a nerve implant, the waterproof, tear-resistant, elastic silk supports cell adhesion, movement, and division.
Tech Briefs: How is nerve/tissue damage traditionally addressed, and how does spider silk improve upon the current repair methods?
Dr. Christine Radtke: I’m a plastic and reconstructive surgeon. Usually when I have a patient that has a gap in the nerve and there is tissue loss, I can transplant a nerve [derived from the individual]. If I have a big nerve injury in the entire arm, I don’t have enough tissue for transplantation. With silk, we can make artificial nerves that we just plop into the nerve gap.
Tech Briefs: What are the characteristics of spider silk that make it such a valuable material for nerve and tissue repair?
Dr. Christine Radtke: For nerve and tissue repair, I need a structure that enhances nerve regeneration and nerve growth. For that, I need a very light and thin material that is both very strong and elastic. This is what I have with spider silk. Compared to many nanomaterials and artificial filaments, the cell growth is just fantastic on the spider silk. Cells align, migrate, and attach to the silk. We haven’t seen this with other materials for nerve regeneration.
Tech Briefs: Take me through your test. How are you able to place the spider silk within the body effectively?
Dr. Christine Radtke: If you have a nerve injury, you may have a nerve gap, a loss of nerve tissue. You need a nerve grown from one side to the other side. Usually it’s very difficult for a nerve to just grow straight and find the other end.
We performed experiments on rodents, rabbits, and large animals like sheep and non-human primates. For the nerve gap, a conduit is developed: We use an acellularized vein, as a tube, filled with longitudinally aligned spider fibers. We can place the construct between the nerve gap to provide nerve guidance structure. If I take the silk and I put it in between those ends, the nerve fibers can grow along the silk and find a linear way, directly, to the nerve at the other end.
Tech Briefs: What were the biggest surprises from your results?
Dr. Christine Radtke: The surprises were that we can bridge larger gaps than we thought: over 6 centimeters, which is currently not possible with other materials on the market.
Tech Briefs: How long have you been working with spider silk?
Dr. Christine Radtke: For more than 15 years. We were originally looking for a fine material that would match with the thin diameter of single nerve fibers. When we began the study, we put spider web fragments into our Schwann cell cultures in the laboratory, and we saw that the fragments attached to the cells.
Tech Briefs: Do you see this being used with humans?
Dr. Christine Radtke: Definitely. Spider silk doesn’t cause any immunological reaction. It’s very well accepted from the body. I’m working here in the university hospital. I see high-end cases where, with regular treatments, we can’t make things better, where we have nothing in our hands. With spider silk, I have new treatments not only regarding nerves, but also with the ability to make the spider silk a skin substitute for burn victims' injuries.
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