Abstract
Tissue engineering aims to create functional tissues for regenerative medicine, where scaffold design and vascular integration remain key challenges. Therefore, the capability to promote vascularization, long-term stability and biocompatibility are important requirements to a scaffold material. One goal is to optimize the cell-to-scaffold material interaction to support vascularization and de novo tissue formation. This study evaluates 3D-printed and non-printed recombinant spider silk protein eADF4(C16)-RGD hydrogels in a rat arteriovenous (AV) loop model. The hydrogels were implanted subcutaneously using polytetrafluorethylene (PTFE) chambers, where the lower half contained an acellular 3D-printed spider silk hydrogel, while the upper half either contained a manually extruded eADF4(C16)-RGD hydrogel without cells (group A) or with T17b endothelial progenitor (EPCs) cells embedded (group B). Constructs were explanted after 2, 4, and 12 weeks. The 3D-printed eADF4(C16)-RGD scaffolds showed good biocompatibility and vascularization. Interestingly, the presence of T17b cells resulted in an increased biodegradation, with the 12 week constructs nearly completely dissolved. The cell-laden constructs showed a significantly increased vascular density per construct area after 4 weeks compared to the cell-free constructs. This study demonstrates that both the scaffold ultrastructure and the integration of T17b cells are effective strategies to enhance the functionality of biomaterials for tissue engineering.