Spider silk protein based materials are known for their good biocompatibility and biodegradability and lack of immunogenicity and allergenicity. For technical processing high amounts of proteins are required, but natural spider silk is rare. Biotechnological production of spider silk proteins gives rise to high yields and allows the genetic modification of the proteins. The recombinantly produced and negatively charged spider silk protein eADF4(C16) is based on the consensus sequence of Araneus diadematus fibroin 4 (ADF4). It contains 16 glutamatic acid residues which can be exchanged with lysine, yielding the positively charged eADF4(k16). The proteins can be processed into films and coatings and the material properties can be adjusted to the desired processing method and fields of application.
Common polymers for medical applications (implants, catheters) are polytetrafluoroethylene (PTFE), polyurethane (PU) and silicone. During application, the performance of biomaterials depends on the biocompatibility which is related to unwanted side effects (foreign body responses and inflammation) and the potential of interaction of cells with its surface. To avoid these problems, it’s important to adjust the material’s surface properties. The first successful application of eADF4(C16) coatings was shown on silicone breast implants to reduce periprosthetic fibrous capsule formation.
The main objective of our research is to design and characterize novel spider silk coatings for biomedical applications. In the distinct application of catheters, low or even no cell adhesion is eligible. To influence the properties of the commonly used biomaterials and to increase their biocompatibility, a thin coating composed of eADF4(k16) acting as adhesion promoter and eADF4(C16) as outer layer was applied on PU, PTFE and silicone and evaluated regarding coating stability, degradation properties and cell adhesion.
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