Natural spider silk enhances mechanical performance of collagen scaffold under stretching conditions

Collagen is the most abundant protein in the extracellular matrix, crucial for wound healing and cell proliferation. While it holds promise as a scaffold for tendon, skin, and ligament reconstruction, collagens mechanical strength, particularly under stretch, is poor. Previous attempts to improve collagen strength involved blending it with silkworm or recombinant spider silk. In this study, for the first time, we evaluated whether collagen gel from fish skin could be strengthened by infusing it with native spider silk, specifically the major ampullate (MA) silk of Nephila pilipes, known for superior mechanical properties. MA silk was woven onto a frame, pressed into a PDMS platform, and then used to create a collagen scaffold. Youngs modulus of the infused collagen scaffold, subjected to either stretching or non-stretching treatments, was measured using AFM. After 24 hours of cyclic stretching, collagen infused with silk showed less fragility, higher Youngs modulus, and no bacterial growth. Immunohistochemical staining showed that after stretching, the thickness and architecture of the collagen gel infused with silk were maintained, and the fibers were reorganized in a more compact, aligned, and denser manner. Overall, collagen infused with native spider silk exhibited improved mechanical stability and stiffness under cyclic stretching, suggesting that this combination could serve as a robust matrix for bioengineering applications while preventing bacterial infiltration.