Silk has excellent biocompatibility and has been used as a surgical thread so far. Using its excellent properties, small diameter artificial blood vessels were produced by electrospinning method from silk solution, and its mechanical properties and internal structure were examined by solid 13C-NMR. As a result, soft nanofiber artificial blood vessels were produced by electrospinning silk sponge and biocompatible segmented polyurethane in a weight ratio of 7: 3 adjusted to HFIP at a concentration of 5wt%. Artificial blood vessel with excellent flexibility was obtained by slowly crystallizing silk nanofiber not by crystallization by immersion in methanol but by exposure to a high humidity atmosphere. Solid NMR measurement revealed that the nanofiber contained a lot of silk-I structure.
