1H MRI study of small-diameter silk vascular grafts in water

Abstract

Small-diameter vascular grafts (VG) made from silk fibroin (SF) fibers by a double-raschel knitting method were prepared by coating their interior and exterior with different materials, such as SF or polyurethane (PU). The 1 H spin density, 1 H spin-spin relaxation time (T 2 ) and diffusion coefficient (D) of the water molecules in the layer of the VG coated by these materials were non-destructively observed in water using 1 H NMR imaging. The inner and outer coating materials significantly affected the amount and mobility of water molecules in the VG. The water content of the SF-coated VG was considerably higher than that of PU-coated VG. The T 2 value of the water molecules in the SF-coated VG layer was smaller than that of the PU-coated VG, which means that the rotational motion of the water molecules in the layer of the SF-coated VG was restricted by the intermolecular interaction between the SF and water molecules. The diffusion coefficient (D) of the water molecules in the SF-coated VG layer was larger than that of the PU-coated VG, indicating that the water molecules were confined to the pores in the graft layer of the PU-coated VG.

Advanced Silk Fibroin Biomaterials and Application to Small-Diameter Silk Vascular Grafts

“…The 1 H spin density, 1 H T 2 , and diffusion coefficient of mobile water molecules in a small-diameter SF vascular graft−water system were also studied using the 1 H MRI method. 146…”

“…The remaining three water reservoirs, B–D, may be assigned to exchangeable water molecules interacting with the SF fiber in three different degrees of binding interactions. The 1 H spin density, 1 H T 2 , and diffusion coefficient of mobile water molecules in a small-diameter SF vascular graft–water system were also studied using the 1 H MRI method …”