Noninvasive Gastrointestinal Tract Imaging Using BSA-Ag 2 Te Quantum Dots as a CT/NIR-II Fluorescence Dual-Modal Imaging Probe in Vivo.

The combination of high-resolution computed tomography (CT) and the real-time sensitive second near-infrared window (NIR-II) fluorescence bioimaging can provide complementary information for the diagnosis, progression and prognosis of gastrointestinal disorders. Ag ₂ Te quantum dots (QDs) are a kind of promising CT/NIR-II fluorescence dual-modal imaging probe due to their high atomic number and narrow bandgap. However, conventional Ag ₂ Te QDs synthesized by oil phase approaches often suffer from complicated steps, harsh reaction conditions, and toxic organic solvents. Herein, we report the synthesis of bovine serum albumin (BSA)-Ag ₂ Te QDs using a biomineralization approach for CT/NIR-II fluorescence dual-modal imaging of the gastrointestinal tract. The BSA-Ag ₂ Te QDs are fabricated in a facile one-pot approach under mild conditions and exhibit homogeneous size, favorable monodispersity, admirable aqueous solubility, excellent X-ray attenuation properties, and outstanding NIR-II fluorescence performance. In vivo imaging experiments show that BSA-Ag ₂ Te QDs can be used in gastrointestinal tract CT/NIR-II dual-modal imaging with high spatiotemporal resolution and sensitivity. In addition, in an intestinal obstruction mouse model, accurate lesion positioning and imaging-guided obstruction relief surgery are successfully realized based on BSA-Ag ₂ Te QDs. Besides, BSA-Ag ₂ Te QDs have outstanding biocompatibility in vitro and in vivo. This study presents a high-performance and biosafe CT/NIR-II fluorescence dual-modal imaging probe for visualizing the gastrointestinal tract in vivo.