Orally administered Bi2S3@SiO2 core-shell nanomaterials as gastrointestinal contrast agents and their influence on gut microbiota

Abstract

Effective and safe contrast agents for X-ray computed tomography (CT) imaging of the gastrointestinal (GI) tract are quite desirable for realizing high diagnostic accuracy and low toxicity in the clinic. Herein, we synthesize a series of silica-coated bismuth sulfide core-shell nanomaterials (Bi₂S₃@SiO₂) of various sizes and systematically study their GI CT contrast performance and potential toxic effects in comparison with those of barium sulfate (BaSO₄) in mice. The <i>in vivo</i> experimental results suggest that these Bi₂S₃@SiO₂ core-shell nanomaterials display superior CT contrast performance and higher elimination efficacy than BaSO₄ by single-dose exposure manner (10 ​mg/kg Bi element/b.w. for Bi₂S₃@SiO₂ versus 30 ​mg/kg Ba element/b.w. for BaSO₄). Furthermore, 28 days after exposure, Bi₂S₃@SiO₂ core-shell nanomaterials show minimal toxic effects <i>in vivo</i> and nonsignificant influences on the structure and function of the gut microbiota in mice. This demonstrates that no adverse effects on the gut homeostasis are induced by Bi₂S₃@SiO₂ core-shell nanomaterials and, thus, suggests that they can act as excellent and safe CT contrast agents for GI tract imaging.