Among the great challenges of modern medicine is the regeneration of human tissue. In this context, functional materials can be tailored for biomedical applications inspired by the blueprint of the natural tissue. The production of hierarchically structured composite materials with biological function will need the incorporation of cells, biopolymers and inorganic components. Spider silk is a suitable candidate as a scaffold material as it shows no immunogenicity, good biocompatibility and biodegradability. Recently, we developed engineered recombinant spider silk proteins based on A. diadematus dragline silk, allowing tailoring these proteins already on a DNA level.1 This biopolymer can be easily processed into a variety of different morphologies, exemplary into hydrogels for 3D (bio)printing applications.2-4 The focus here is the incorporation of biominerals by various methods,5 yielding specialized scaffolds for tissue regeneration applications in terms of hard tissue development. The negatively charged spider silk variant eADF4(C16) displays multiple carboxylate moieties which are capable of binding cations.5 These charge dependent effects can be used to mineralize scaffolds in a post-treatment process. Further, the incorporation can be realized by seeding inorganic particles directly into a soft hydrogel matrix for 3D printing applications.
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 DeSimone, E.; Schacht, K.; Pellert, A.; Scheibel, T., Biofabrication 2017, 9 (4), 044104.
 Hardy, J. G.; Torres-Rendon, J. G.; Leal-Egana, A.; Walther, A.; Schlaad, H.; Coelfen, H.; Scheibel, T. R., Materials 2016, 9 (7).