Efficient dual-imaging platform: Ultrasound-driven synthesis of bismuth–iron oxide nanocomposites

Nanoparticle (NP)-based imaging probes exhibit significantly greater payload and longer blood circulation duration compared to small molecule contrast agents (CAs). Enhanced dual-modal imaging (MRI and CT) combines the great spatial resolution of magnetic resonance imaging (MRI) with the strong radiodensity of computed tomography (CT) to enable early and accurate illness diagnosis. Synthesized Bi–Fe₃O₄ composite NPs are biocompatible and safe, crucial for in vivo clinical applications. The use of a rapid and straightforward, ultrasound-assisted synthesis process and green chemistry, specifically natural plant extract (Sumac) as a stabilizer, demonstrates a sustainable approach to nanomaterial development that minimizes environmental impact while maintaining high functional performance. The physicochemical properties of the Bi–Fe₃O₄ were assessed using a range of typical analyses. The resulting composite NPs exhibited uniformity, crystallinity, semi-spherical shapes, and superparamagnetic properties, with an average size of 17.5 nm and a magnetization value of 92 emu/g. Furthermore, the research investigated the cytotoxicity, intracellular distribution, and cellular internalization of Bi–Fe₃O₄ composite NPs using flow cytometry, the MTT assay, and Prussian blue staining. The findings indicated that the composite NPs were non-toxic, biocompatible, and dose-dependent under exposure conditions. The sensitivity, relaxivity, and attenuation characteristics of the colloid sample were evaluated for their potential dual-modal MRI/CT contrast enhancement using agarose gel-based phantoms. The Bi component exhibited an exceptionally high X-ray attenuation property of 399 HU, while the Fe₃O₄ component showed remarkable magnetization (92 emu/g) and transverse relaxation (r₂ = 273 mM⁻¹ s⁻¹) shortening capabilities.