Noninvasive diagnosis of diverse gastrointestinal disorders using tantalum-rich carbon dots as an X-ray contrast agent

Abstract

Gastrointestinal (GI) diseases pose significant diagnostic challenges due to nonspecific early symptoms and the difficulty in detecting subtle lesions. Dynamic X-ray imaging and high spatial-resolution computed tomography (CT) provide flexible and powerful tools for the precise diagnosis of diverse GI diseases. However, current clinical X-ray contrast agents still present inherent limitations, as BaSO4 exhibits poor water solubility and iodine-based small molecules encounter issues of iodine allergy, contraindications, and generally low sensitivity. Here we report noninvasive diagnosis of diverse gastrointestinal disorders using tantalum-rich carbon dots (Ta-rCDs) as an X-ray contrast agent. Ta-rCDs are prepared through a simple and scalable high-temperature carbonization process, featuring ultrahigh tantalum content (∼48%), gram-scale yield (3.2 g per batch), ultrasmall hydrodynamic size (∼3 nm), excellent water solubility (>500 mg/mL) and strong X-ray attenuation. In models of small-intestinal stricture and esophageal leakage, Ta-rCDs enable simultaneous dynamic X-ray tracking and high-resolution CT imaging, allowing the visualization of microlesions and demonstrating efficient renal excretion upon entering the peritoneal cavity. Systematic biocompatibility assessments further confirm their good biosafety. Together these findings offered a noninvasive, real-time and high-sensitivity strategy for accurate diagnosis and monitoring of GI diseases.