Fabrication of gelatin BiS capsules as a highly sensitive X-ray contrast agent for gastrointestinal motility assessment .

Tiny BaSO rod-based X-ray imaging is the most frequently-used method for clinical diagnosis of gastrointestinal motility disorders. The BaSO rods usually have a small size to pass through the gastrointestinal tract smoothly, but suffer from unavoidably low sensitivity. Herein, we developed BiS capsules as a high-performance X-ray contrast agent for gastrointestinal motility assessment for the first time. The BiS capsules were synthesized by the encapsulation of commercial BiS powder into commercial gelatin capsules and subsequent coating of ultraviolet-curable resin. The prepared BiS capsules showed excellent biocompatibility and and superior X-ray attenuation ability due to the large atomic number and high K-edge value of Bi. The developed BiS capsules can serve as a small but highly sensitive X-ray contrast agent to quantitatively assess gastrointestinal motility in a vincristine-induced gastrointestinal motility disorder model by X-ray, CT and spectral CT imaging successfully, solving the intrinsic drawbacks of clinically used BaSO.