Facile synthesis of ultrasmall Bi2O3 nanoparticles for computed tomography imaging

https://doi.org/10.62239/jca.2025.062

Abstract

Ultrasmall bismuth oxide nanoparticles (Bi₂O₃ NP) are emerging as promising CT contrast agents owing to their high atomic number, strong X-ray attenuation, and versatile surface chemistry. Herein, we report a facile one-pot polyol synthesis of Bi₂O₃ NPs using triethylene glycol and polyacrylic acid (PAA), which acts as both surfactant and biocompatible coating. The obtained Bi₂O₃@PAA NPs exhibit an average core size of ~4.4 nm, uniform dispersion, and excellent aqueous stability. Their structural and surface characteristics were comprehensively confirmed by TEM, XRD, DLS, FTIR and TGA analyses. In vitro CT imaging experiments demonstrated that Bi₂O₃@PAA NPs produced a linear and concentration-dependent enhancement in Hounsfield units (HU), achieving an X-ray attenuation efficiency significantly higher than that of the commercial iodine-based contrast agent iobitridol under identical conditions. These findings highlight the potential of ultrasmall Bi₂O₃@PAA NPs as next-generation CT contrast agents.