Adjusted material-cell interaction using engineered spider silk proteinsPart of:
Spider silks are biodegradable, biocompatible, hypoallergenic, non-inflammatory and show extraordinary mechanical properties, including high elasticity and strength (1). Therefore, they combine interesting features for medical, clinical and pharmaceutical applications (2). A recombinant spider silk protein was designed and produced in a biotechnological process using E.coli to ensure generation of high amounts with consistent, reproducible properties (3,4). After encoding the amino acid composition of the dragline silk from Araneus diadematus, it was possible to develop naturally inspired, but recombinantly produced spider silk proteins, such as the 16 times repeated engineered Araneus diadematus fibroin 4, shortly eADF4(C16) (4). Engineered proteins exhibit similar properties to the naturally occurring spider silk, but also allow for high-yield production (4). As eADF4(C16) doesn’t contain specific cell adhesive motifs, cells, for example BALB/3T3 mouse fibroblasts, display low adhesion and proliferation on scaffolds made of these spider silk proteins (5). Thus, it is essential to adjust the cell binding properties by functionalizing the engineered spider silk protein eADF4(C16) to promote cell interaction (6-10). In this context, the recombinant silk protein eADF4(C16) was modified by genetically fusing the integrin recognition sequence RGD (7). The fusion protein eADF4(C16)-RGD showed similar properties to the unmodified spider silk protein with the exception of an improved cell attachment and proliferation as seen on RGD-silk films (7) or hydrogels (11). Although these results have shown the biomedical potential of these proteins, there is still room for further development in the future. In particular, the combination of cells and materials within tissue-like structures using one fabrication process, also known as biofabrication, is in our focus.