Gram-Scale Synthesis\nof Renal-Clearable Tantalum Nanodots\nwith High Water Solubility for Computed Tomography Imaging In Vivo

Tantalum (Ta) emerges as a promising element for advanced\ncomputed\ntomography (CT) imaging probes owing to its high X-ray attenuation\ncoefficient and excellent biocompatibility. Nevertheless, the synthesis\nof renally clear Ta-based imaging probes through simple methods remains\na significant challenge. Herein, we introduce a simple and gram-scale\napproach for the synthesis of renal-clearable Ta nanodots with high\nwater solubility for CT imaging in vivo. The Ta nanodots, coordination\npolymers, are fabricated via coordination reactions involving Ta(OH)<sub>5</sub>, citric acid (CA), and hydrogen peroxide. The Ta nanodots\nexhibit an ultrasmall hydrodynamic diameter (2.8 nm), high water solubility\n(1.88 g/mL, 688 mg Ta/mL), superior X-ray absorption capacity, gram-scale\nproduction capability (>10 g in lab synthesis), renal-clearable\nability,\nand good biocompatibility. The Ta nanodots possess superior CT imaging\nefficacy across diverse tube voltages, enabling highly sensitive gastrointestinal\nCT imaging, renal CT imaging, and CT angiography (CTA). Moreover,\nTa nanodots maintain robust CT imaging capabilities even at high X-ray\nenergies, and Ta nanodots-based spectral CT achieves metallic artifacts-minimized\nCTA. The proposed Ta nanodots present substantial potential as a potent\nCT imaging probe for diagnosing various diseases.